feat(indexes): Support for CONCURRENTLY modifying indexes and indexing column operator class

[hackermondev]

New Features

• Adds support for creating and dropping indexes concurrently
  https://www.postgresql.org/docs/current/sql-createindex.html#SQL-CREATEINDEX-CONCURRENTLY
• Adds support for specifying operator classes with index columns (closes Support for specifying operator class in expression indexes (e.g. gist_trgm_ops) #907)

Both changes are Postgres only.

[Expurple]

Thanks! Do you want to backport this to 0.32.x branch too? (the one used in the current SeaORM 1.1.x)

[hackermondev]

Thanks! Do you want to backport this to 0.32.x branch too? (the one used in the current SeaORM 1.1.x)

Yeah, would I have to create a new PR?

[hackermondev]

I'm going to add to the PR to support Postgres index operator classes. Should close #907

[Expurple]

Yeah, a separate PR against 0.32.x. You should be able to rebase/cherry-pick your commit with little-to-no conflicts in this area.

Move operator classes into separate PRs, please

[tyt2y3]

I can do the backporting to 0.32. though it'd be great to break down the PR into two, one for each feature.

[hackermondev]

Sorry for the long wait. I've created 2 separate PRs.
#963 #964

There might be some merge conflicts with the tests (since the test names are sequentially ordered), but those should be easily fixable.

[Expurple]

Thank you. Let's close this one then