Log when a trace is too large to compact

[scalalang2]

What this PR does:
Log when a trace is too large to compact.
If the total bytes of traces exceeds maximum limit, the following messages will be logged.

{
    "msg": "max size of trace exceeded",
    "tenant": "XXXXX",
    "traceId": "XXXXX",
    "discarded_span_count": 100
}

There will be some dicussions in this PR.
Please refer to following comments.

Which issue(s) this PR fixes:
Fixes #1931

Checklist

• Tests updated
• Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]

[joe-elliott]

two comments. looking good!

[joe-elliott]

this is looking good. two small comments.

i forgot that v2 and vParquet have different paths for counting dropped spans. thank you for tracking this down. i suppose ultimately we'd prefer both act like vParquet does, but that's too much change for this PR.

[joe-elliott]

Nice! Thanks for this improvement. It looks like there's a conflict in the changelog. If you can clean that up we'll merge.

[scalalang2]

I cleaned changelog, thanks joe :)