feat(modules): Rewrite core, orchestrate AppRoles for minions

This commit represents a fundamental rewrite in how Salt interacts with
Vault. The master should still be compatible with minions running the
old code. There should be no breaking changes to public interfaces and
the old configuration format should still apply.

Core:
- Issue AppRoles to minions
- Manage entities with templatable metadata for minions
- Use inbuilt Salt cache
- Separate config cache from token cache
- Cache: introduce connection-scope vs global scope

Utility module:
- Support being imported (__utils__ deprecation)
- Raise exceptions on queries to simplify response handling
- Add classes to wrap complexity, especially regarding KV v2
- Lay some groundwork for renewing tokens

Execution module:
- Add patch_secret
- Add version support to delete_secret
- Allow returning listed keys only in list_secret
- Add policy_[fetch/write/delete] and policies_list
- Add query for arbitrary API queries

State module:
- Make use of execution module
- Change output format

Docs:
- Update for new configuration format
- Correct examples
- Add configuration examples
- Add required policies

Fixes:
saltstack/salt#62552
saltstack/salt#59827
saltstack/salt#62380
saltstack/salt#58174

Probably fixes:
saltstack/salt#60779
saltstack/salt#57561

Might fix:
saltstack/salt#59846