Remove per chart configuration. (#12728)

After https://github.com/netdata/netdata/pull/12209 per-chart configuration
was used for (a) enabling/disabling a chart, and (b) renaming dimensions.

Regarding the first use case: We already have component-specific
configuration options|flags to finely control how a chart should behave.
Eg. "send charts matching" in streaming, "charts to skip from training"
in ML, etc. If we really need the concept of a disabled chart, we can
add a host-level simple pattern to match these charts.

Regarding the second use case: It's not obvious why we'd need to provide
support for remapping dimension names through a chart-specific configuration
from the core agent. If the need arises, we could add such support at
the right place, ie. a exporter/streaming config section.

This will allow each flag to act indepentendly from each other and
avoid managing flag-state manually at various places, eg:

```
    if(unlikely(!rrdset_flag_check(st, RRDSET_FLAG_ENABLED))) {
        rrdset_flag_clear(st, RRDSET_FLAG_UPSTREAM_SEND);
        rrdset_flag_set(st, RRDSET_FLAG_UPSTREAM_IGNORE);
    } ...
```

1 files changed, 4 insertions, 3 deletions

diff --git a/database/rrddim.c b/database/rrddim.c
index ebb31996b2..bca86b7373 100644
--- a/database/rrddim.c
+++ b/database/rrddim.c
@@ -43,9 +43,10 @@ inline int rrddim_set_name(RRDSET *st, RRDDIM *rd, const char *name) {
 
     debug(D_RRD_CALLS, "rrddim_set_name() from %s.%s to %s.%s", st->name, rd->name, st->name, name);
 
-    char varname[CONFIG_MAX_NAME + 1];
-    snprintfz(varname, CONFIG_MAX_NAME, "dim %s name", rd->id);
-    rd->name = config_set_default(st->config_section, varname, name);
+    if (rd->name)
+        freez((void *) rd->name);
+
+    rd->name = strdupz(name);
     rd->hash_name = simple_hash(rd->name);
 
     if (!st->state->is_ar_chart)