Use sync.Pools in otlploghttp transforms

[MrAlias]

Could we use sync.Pools to reduce the amount of heap allocation?
E.g. ResourceLogs could return a functions that would return the pooled maps and slices back to their pools.

If you think that it is possible and it is a good idea then this should be tracked as a separate issue.

Originally posted by @pellared in #5191 (comment)

[hiroyaonoe]

I want to work on this!
Should I update ScopeLogs as well?

opentelemetry-go/exporters/otlp/otlplog/otlploghttp/internal/transform/log.go

Line 56 in fe3de70

func ScopeLogs(records []log.Record) []*lpb.ScopeLogs {

[MrAlias]

I want to work on this! Should I update ScopeLogs as well?

opentelemetry-go/exporters/otlp/otlplog/otlploghttp/internal/transform/log.go

Line 56 in fe3de70

func ScopeLogs(records []log.Record) []*lpb.ScopeLogs {

I would start by only pooling the maps.