services/horizon: Use COPY to speed up ClaimableBalanceChangeProcessor

[urvisavla]

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

Use FastBatchInsertBuilder for writing to claimable_balances and claimable_balance_claimants tables. FastBatchInsertBuilder uses ‘COPY' to insert into the db which is faster than using 'INSERT'.

Why

#5086

Known limitations

[TODO or N/A]

[urvisavla]

As shown in the Ingestion Processor Run Duration graph below, deploying the build with COPY instead of insert to staging significantly reduced the processing time required by the ClaimableBalanceChangeProcessor for the same network activity in claimable balances.