Update Feast Serving documentation with ways to run and debug locally

[adchia]

What this PR does / why we need it:
Removes old documentation for Feast Serving and adds new instructions for debugging locally

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?:

NONE

[codecov-commenter]

Codecov Report

Merging #2272 (39660fa) into master (6e30457) will decrease coverage by 27.22%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           master    #2272       +/-   ##
===========================================
- Coverage   85.82%   58.59%   -27.23%     
===========================================
  Files         116      116               
  Lines        9790     9809       +19     
===========================================
- Hits         8402     5748     -2654     
- Misses       1388     4061     +2673     

Flag	Coverage Δ
integrationtests	?
unittests	58.59% <ø> (+0.07%)	⬆️

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

Impacted Files	Coverage Δ
.../integration/online_store/test_universal_online.py	15.00% <0.00%> (-82.92%)	⬇️
.../integration/online_store/test_online_retrieval.py	17.39% <0.00%> (-82.61%)	⬇️
sdk/python/tests/utils/online_read_write_test.py	20.68% <0.00%> (-79.32%)	⬇️
...fline_store/test_universal_historical_retrieval.py	23.50% <0.00%> (-76.50%)	⬇️
...gration/registration/test_feature_service_apply.py	31.25% <0.00%> (-68.75%)	⬇️
sdk/python/feast/infra/online_stores/redis.py	26.45% <0.00%> (-68.39%)	⬇️
sdk/python/tests/integration/e2e/test_usage_e2e.py	33.87% <0.00%> (-66.13%)	⬇️
sdk/python/feast/infra/utils/snowflake_utils.py	23.36% <0.00%> (-65.43%)	⬇️
sdk/python/tests/data/data_creator.py	34.78% <0.00%> (-65.22%)	⬇️
...dk/python/tests/integration/e2e/test_validation.py	35.18% <0.00%> (-64.82%)	⬇️
... and 61 more

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[felixwang9817]

/lgtm

[feast-ci-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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