[FSTORE-1795] Update api to use data source and deprecate direct storage connector usage

[bubriks]

This PR adds/fixes/changes...

• please summarize your changes to the code
• and make sure to include all changes to user-facing APIs

JIRA Issue: -

Priority for Review: -

Related PRs: -

How Has This Been Tested?

• Unit Tests
• Integration Tests
• Manual Tests on VM

Checklist For The Assigned Reviewer:

- [ ] Checked if merge conflicts with master exist
- [ ] Checked if stylechecks for Java and Python pass
- [ ] Checked if all docstrings were added and/or updated appropriately
- [ ] Ran spellcheck on docstring
- [ ] Checked if guides & concepts need to be updated
- [ ] Checked if naming conventions for parameters and variables were followed
- [ ] Checked if private methods are properly declared and used
- [ ] Checked if hard-to-understand areas of code are commented
- [ ] Checked if tests are effective
- [ ] Built and deployed changes on dev VM and tested manually
- [x] (Checked if all type annotations were added and/or updated appropriately)

[kennethmhc]

looks good, few questions

[kennethmhc]

can you infer from feature_group.data_source.query as well?

[bubriks]

yes query works.
here is an example:

def create_external_feature_group():
    data_source = fs.get_data_source("rds")

    # using table
    #data_source = data_source.get_tables("postgres")[0]

    # using query
    data_source.query = "SELECT * FROM postgres.public.users"

    fs.create_external_feature_group(
        name="users_test_query",
        version=2,
        primary_key=["id"],
        data_source=data_source
    ).save()