WIP: attempt bufbuild conversion

[zalegrala]

What this PR does:

Which issue(s) this PR fixes:
Fixes #

TODO

• tempopb.PreallocBytes needs handling. This was dropped with gogoproto, but I don't see an alternative solution. Needs research.
• MarshalToSizedBuffer is not handled, I'm not clear on the intent
• In order to fully test, I believ dskit also needs updating? Unsure how pyroscope worked around this, to investigate.

Checklist

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