Add init to Provider contract

[woop]

What this PR does / why we need it:

This PR adds an abstract __init__ as part of the base class for Providers. Currently no such method exists which has led to custom providers and built in providers having different initialization contracts.

feast/sdk/python/feast/infra/provider.py

Line 146 in 745a1b4

return GcpProvider(config)

vs

feast/sdk/python/feast/infra/provider.py

Line 164 in 745a1b4

return cls(config, repo_path)

Does this PR introduce a user-facing change?:

All custom providers must now provide an initialization method and won't receive a repo_path argument

[codecov-commenter]

Codecov Report

Merging #1796 (729759e) into master (a48bcd0) will decrease coverage by 20.94%.
The diff coverage is 50.00%.

@@             Coverage Diff             @@
##           master    #1796       +/-   ##
===========================================
- Coverage   84.85%   63.90%   -20.95%     
===========================================
  Files          92       89        -3     
  Lines        6826     6719      -107     
===========================================
- Hits         5792     4294     -1498     
- Misses       1034     2425     +1391     

Flag	Coverage Δ
integrationtests	?
unittests	63.90% <50.00%> (-0.03%)	⬇️

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

Impacted Files	Coverage Δ
sdk/python/feast/infra/provider.py	84.07% <50.00%> (-5.03%)	⬇️
.../integration/online_store/test_universal_online.py	16.32% <0.00%> (-83.68%)	⬇️
.../integration/online_store/test_online_retrieval.py	17.39% <0.00%> (-82.61%)	⬇️
sdk/python/tests/utils/online_read_write_test.py	18.18% <0.00%> (-81.82%)	⬇️
...fline_store/test_universal_historical_retrieval.py	20.25% <0.00%> (-79.75%)	⬇️
...gration/registration/test_feature_service_apply.py	31.25% <0.00%> (-68.75%)	⬇️
...hon/tests/integration/registration/test_cli_gcp.py	31.70% <0.00%> (-68.30%)	⬇️
...n/tests/integration/registration/test_cli_redis.py	32.55% <0.00%> (-67.45%)	⬇️
sdk/python/feast/infra/online_stores/redis.py	30.35% <0.00%> (-64.29%)	⬇️
sdk/python/feast/infra/online_stores/datastore.py	31.03% <0.00%> (-62.07%)	⬇️
... and 38 more

---

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[achals]

/lgtm

[feast-ci-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: achals, woop

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• OWNERS [achals,woop]

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[feast-ci-bot]

New changes are detected. LGTM label has been removed.