:sparkles: Implement Page bundling and image handling

This commit is not the smallest in Hugo's history.

Some hightlights include:

* Page bundles (for complete articles, keeping images and content together etc.).
* Bundled images can be processed in as many versions/sizes as you need with the three methods `Resize`, `Fill` and `Fit`.
* Processed images are cached inside `resources/_gen/images` (default) in your project.
* Symbolic links (both files and dirs) are now allowed anywhere inside /content
* A new table based build summary
* The "Total in nn ms" now reports the total including the handling of the files inside /static. So if it now reports more than you're used to, it is just **more real** and probably faster than before (see below).

A site building  benchmark run compared to `v0.31.1` shows that this should be slightly faster and use less memory:

```bash
▶ ./benchSite.sh "TOML,num_langs=.*,num_root_sections=5,num_pages=(500|1000),tags_per_page=5,shortcodes,render"

benchmark                                                                                                         old ns/op     new ns/op     delta
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      101785785     78067944      -23.30%
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     185481057     149159919     -19.58%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      103149918     85679409      -16.94%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     203515478     169208775     -16.86%

benchmark                                                                                                         old allocs     new allocs     delta
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      532464         391539         -26.47%
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     1056549        772702         -26.87%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      555974         406630         -26.86%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     1086545        789922         -27.30%

benchmark                                                                                                         old bytes     new bytes     delta
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      53243246      43598155      -18.12%
BenchmarkSiteBuilding/TOML,num_langs=1,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     105811617     86087116      -18.64%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=500,tags_per_page=5,shortcodes,render-4      54558852      44545097      -18.35%
BenchmarkSiteBuilding/TOML,num_langs=3,num_root_sections=5,num_pages=1000,tags_per_page=5,shortcodes,render-4     106903858     86978413      -18.64%
```

Fixes #3651
Closes #3158
Fixes #1014
Closes #2021
Fixes #1240
Updates #3757

1 files changed, 15 insertions, 27 deletions

diff --git a/commands/list.go b/commands/list.go
index b2a6b5395..b391f204e 100644
--- a/commands/list.go
+++ b/commands/list.go
@@ -43,20 +43,16 @@ var listDraftsCmd = &cobra.Command{
 	Short: "List all drafts",
 	Long:  `List all of the drafts in your content directory.`,
 	RunE: func(cmd *cobra.Command, args []string) error {
-
-		cfg, err := InitializeConfig()
-		if err != nil {
-			return err
+		cfgInit := func(c *commandeer) error {
+			c.Set("buildDrafts", true)
+			return nil
 		}
-
-		c, err := newCommandeer(cfg)
+		c, err := InitializeConfig(false, cfgInit)
 		if err != nil {
 			return err
 		}
 
-		c.Set("buildDrafts", true)
-
-		sites, err := hugolib.NewHugoSites(*cfg)
+		sites, err := hugolib.NewHugoSites(*c.DepsCfg)
 
 		if err != nil {
 			return newSystemError("Error creating sites", err)
@@ -84,20 +80,16 @@ var listFutureCmd = &cobra.Command{
 	Long: `List all of the posts in your content directory which will be
 posted in the future.`,
 	RunE: func(cmd *cobra.Command, args []string) error {
-
-		cfg, err := InitializeConfig()
-		if err != nil {
-			return err
+		cfgInit := func(c *commandeer) error {
+			c.Set("buildFuture", true)
+			return nil
 		}
-
-		c, err := newCommandeer(cfg)
+		c, err := InitializeConfig(false, cfgInit)
 		if err != nil {
 			return err
 		}
 
-		c.Set("buildFuture", true)
-
-		sites, err := hugolib.NewHugoSites(*cfg)
+		sites, err := hugolib.NewHugoSites(*c.DepsCfg)
 
 		if err != nil {
 			return newSystemError("Error creating sites", err)
@@ -125,20 +117,16 @@ var listExpiredCmd = &cobra.Command{
 	Long: `List all of the posts in your content directory which has already
 expired.`,
 	RunE: func(cmd *cobra.Command, args []string) error {
-
-		cfg, err := InitializeConfig()
-		if err != nil {
-			return err
+		cfgInit := func(c *commandeer) error {
+			c.Set("buildExpired", true)
+			return nil
 		}
-
-		c, err := newCommandeer(cfg)
+		c, err := InitializeConfig(false, cfgInit)
 		if err != nil {
 			return err
 		}
 
-		c.Set("buildExpired", true)
-
-		sites, err := hugolib.NewHugoSites(*cfg)
+		sites, err := hugolib.NewHugoSites(*c.DepsCfg)
 
 		if err != nil {
 			return newSystemError("Error creating sites", err)