Add CLI parameters for move-tables feature

[danieljoos]

A Pull Request should be associated with an Issue.

We wish to have discussions in Issues. A single issue may be targeted by multiple PRs.
If you're offering a new feature or fixing anything, we'd like to know beforehand in Issues,
and potentially we'll be able to point development in a particular direction.

Related issue (public): #1681
Related issue (internal): https://github.com/github/database-infrastructure/issues/8167

Further notes in https://github.com/github/gh-ost/blob/master/.github/CONTRIBUTING.md
Thank you! We are open to PRs, but please understand if for technical reasons we are unable to accept each and any PR

Description

This PR is part of the move-tables feature development PR stack.
It introduces CLI flags for enabling the move-tables mode and to specify the destination database.

In case this PR introduced Go code changes:

• contributed code is using same conventions as original code
• script/cibuild returns with no formatting errors, build errors or unit test errors.