services/galexie: Add replace (overwrite) command.

[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 reviewed the changes in this PR and if I consider them worthwhile for being mentioned on release notes then I have updated the relevant CHANGELOG.md within the component folder structure. For example, if I changed horizon, then I updated (services/horizon/CHANGELOG.md. I add a new line item describing the change and reference to this PR. If I don't update a CHANGELOG, I acknowledge this PR's change may not be mentioned in future release notes.
• 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

Add a new command replace to re-export of all ledgers within a specified range, overwriting any existing data in the data lake. It is restricted to bounded mode.

Why

stellar/stellar-galexie#5

Known limitations

The command uses a single PutFile operation and does not check for the existence. So, the uploader cannot distinguish between a new file and an overwritten one. Therefore, for metrics logging label already_exists will always be recorded as an empty string.

[sreuland]

nice work and test coverage! left a few comments for consideration, nothing blocking.

[tamirms]

left a few comments for minor issues but, overall, this looks good!