docs: Improve quickstart to include push features, batch scoring, odfv

[adchia]

What this PR does / why we need it:
This PR expands the default quickstart templates to include more functionality such as push features, multiple feature services, multiple ways of retrieving features, and on demand features.

It also moves the auto generated repository into a feature_repo folder, and adds READMEs in them on what else is needed to get to production. This is to prep for a future PR that includes GitHub actions that automatically apply definitions to a remote registry.

A followup will update the quickstart Colab to do some of the same things

Which issue(s) this PR fixes:

Fixes #

[codecov-commenter]

Codecov Report

Merging #3034 (87c43fe) into master (5b0cc87) will increase coverage by 8.86%.
The diff coverage is 87.50%.

@@            Coverage Diff             @@
##           master    #3034      +/-   ##
==========================================
+ Coverage   66.93%   75.79%   +8.86%     
==========================================
  Files         173      207      +34     
  Lines       15056    17076    +2020     
==========================================
+ Hits        10077    12943    +2866     
+ Misses       4979     4133     -846     

Flag	Coverage Δ
integrationtests	66.94% <12.50%> (+0.01%)	⬆️
unittests	58.26% <87.50%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
sdk/python/feast/feature_store.py	85.47% <ø> (+3.61%)	⬆️
sdk/python/feast/feature_view.py	96.66% <ø> (ø)
sdk/python/tests/doctest/test_all.py	90.00% <80.00%> (+74.74%)	⬆️
sdk/python/feast/repo_operations.py	48.62% <100.00%> (+24.77%)	⬆️
sdk/python/tests/unit/cli/test_cli_chdir.py	100.00% <100.00%> (+81.48%)	⬆️
...k/python/tests/unit/local_feast_tests/test_init.py	100.00% <100.00%> (+81.08%)	⬆️
.../python/feast/infra/feature_servers/base_config.py	100.00% <0.00%> (ø)
...n/feast/infra/feature_servers/aws_lambda/config.py	100.00% <0.00%> (ø)
...thon/feast/infra/utils/postgres/postgres_config.py	100.00% <0.00%> (ø)
...b/cassandra_online_store/cassandra_online_store.py	2.63% <0.00%> (ø)
... and 112 more

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[felixwang9817]

some initial comments, will do another pass later

[felixwang9817]

looks good!

[felixwang9817]

/lgtm

[feast-ci-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: adchia, felixwang9817

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[felixwang9817]

/lgtm

[feast-ci-bot]

New changes are detected. LGTM label has been removed.