Support API Key Authentication

[EngHabu]

TL;DR

Adds support for API KEY authentication. Since not all OAuth Providers support API Keys, this implementation is client-side only.

Type

• [ ] Bug Fix
• [X] Feature
• [ ] Plugin

Are all requirements met?

• [X] Code completed
• [X] Smoke tested
• [ ] Unit tests added
• [ ] Code documentation added
• [ ] Any pending items have an associated Issue

Complete description

While API Keys are very prevalent for client side tools/libraries to access services, there aren't good standards around generating, maintaining, rotating, expiring them. This implementation makes use of ClientSecret OAuth2 flow, which is standard, to provide the convenience of API Key auth (a single string w/ minimum settings/knobs).

It assumes an API KEY provided is a base64 encoded json string:

{
  "client_id": "abc",
  "client_secret": "def"
}

Generating an API Key:

echo '{"client_id":"abc","client_secret":"def"}' | base64 

With this change, a simple config file like:

admin:
  endpoint: dns:///my-end-point

Is enough to invoke pyflyte like this:

FLYTE_CREDENTIALS_API_KEY=eyJjbGllbnRfaWQiOiJhYmMiLCJjbGllbnRfc2VjcmV0IjoiZGVmIn0K pyflyte run --remote my_wp.py wf

Tracking Issue

https://github.com/flyteorg/flyte/issues/

Follow-up issue

NA OR https://github.com/flyteorg/flyte/issues/

[codecov[bot]]

Codecov Report

Merging #1569 (9755738) into master (0a1f289) will decrease coverage by 0.11%. The diff coverage is 33.33%.

@@            Coverage Diff             @@
##           master    #1569      +/-   ##
==========================================
- Coverage   71.27%   71.16%   -0.11%     
==========================================
  Files         334      334              
  Lines       30502    30557      +55     
  Branches     5514     5526      +12     
==========================================
+ Hits        21739    21747       +8     
- Misses       8221     8261      +40     
- Partials      542      549       +7     

Impacted Files	Coverage Δ
flytekit/configuration/internal.py	15.38% <0.00%> (-0.84%)	:arrow_down:
flytekit/clients/auth_helper.py	37.93% <28.57%> (-7.28%)	:arrow_down:
flytekit/configuration/__init__.py	35.54% <35.13%> (-1.76%)	:arrow_down:
flytekit/clis/sdk_in_container/helpers.py	84.84% <66.66%> (+0.97%)	:arrow_up:
flytekit/clients/auth/authenticator.py	52.03% <100.00%> (+0.39%)	:arrow_up:

... and 2 files with indirect coverage changes