services/horizon: Add metrics to all builders that embed BatchInsertBuilder

[bartekn]

PR Checklist

PR Structure

• This PR has reasonably narrow scope (if not, break it down into smaller PRs).
• This PR avoids mixing refactoring changes with feature changes (split into two PRs
  otherwise).
• This PR's title starts with name of package that is most changed in the PR, ex.
  services/friendbot, or all or doc if the changes are broad or impact many
  packages.

Thoroughness

• This PR adds tests for the most critical parts of the new functionality or fixes.
• I've updated any docs (developer docs, .md
  files, etc... affected by this change). Take a look in the docs folder for a given service,
  like this one.

Release planning

• I've updated the relevant CHANGELOG (here for Horizon) if
  needed with deprecations, added features, breaking changes, and DB schema changes.
• I've decided if this PR requires a new major/minor version according to
  semver, or if it's mainly a patch change. The PR is targeted at the next
  release branch if it's not a patch change.

What

Reuse route label in db metrics to gather metrics for specific queries.

Why

This is done to understand what's the time spent in specific queries. It helps debugging issues like the slow TransactionsProcessor. After gathering new metrics we can see that it's actually DB operations that take significant time in this processor:

horizon_db_query_duration_seconds{error="false",query_type="insert",route="transactionBatchInsertBuilder",subservice="ingest",quantile="0.5"} 0.114881944
horizon_db_query_duration_seconds{error="false",query_type="insert",route="transactionBatchInsertBuilder",subservice="ingest",quantile="0.9"} 0.183986877
horizon_db_query_duration_seconds{error="false",query_type="insert",route="transactionBatchInsertBuilder",subservice="ingest",quantile="0.99"} 0.374664138
horizon_db_query_duration_seconds_sum{error="false",query_type="insert",route="transactionBatchInsertBuilder",subservice="ingest"} 34.911868006000006
horizon_db_query_duration_seconds_count{error="false",query_type="insert",route="transactionBatchInsertBuilder",subservice="ingest"} 280

horizon_ingest_processor_run_duration_seconds{name="processors.TransactionProcessor",quantile="0.5"} 0.124784865
horizon_ingest_processor_run_duration_seconds{name="processors.TransactionProcessor",quantile="0.9"} 0.197986801
horizon_ingest_processor_run_duration_seconds{name="processors.TransactionProcessor",quantile="0.99"} 0.386869168
horizon_ingest_processor_run_duration_seconds_sum{name="processors.TransactionProcessor"} 37.35023348499998
horizon_ingest_processor_run_duration_seconds_count{name="processors.TransactionProcessor"} 280

Known limitations

It would be clean to create a new label like method or query but it will create a new dimension on all existing metrics with route set increasing space requirements for metrics.

[2opremio]

I think it's missing a couple of processors which don't have custom insert builders.

[bartekn]

Moving this back to draft status because it's not that urgent and maybe will be replaced by #4094.