SNOW-1665707: Move general.py into src/…/modin/plugin/extensions/

[sfc-gh-helmeleegy]

1. Which Jira issue is this PR addressing? Make sure that there is an accompanying issue to your PR.

   Fixes SNOW-1665707

2. Fill out the following pre-review checklist:

   • I am adding a new automated test(s) to verify correctness of my new code
     • If this test skips Local Testing mode, I'm requesting review from @snowflakedb/local-testing
   • I am adding new logging messages
   • I am adding a new telemetry message
   • I am adding new credentials
   • I am adding a new dependency
   • If this is a new feature/behavior, I'm adding the Local Testing parity changes.

3. Please describe how your code solves the related issue.

   Move general.py into src/…/modin/plugin/extensions/. Also, re-organize the properties/methods in the file to match pandas documentation.

[sfc-gh-azhan]

It's hard for me to know what the real changes are in this version. Can we decouple this into smaller PRs?

[sfc-gh-helmeleegy]

It's hard for me to know what the real changes are in this version. Can we decouple this into smaller PRs?

Unfortunately, diff is doing a very bad job. Just look at the complete new file, and you'll find that now the methods/properties are following the same order as the pandas docs and their pandas categories are added as comments.