Integrate ubi-manifest [RHELDST-8706]

[rbikar]

This change introduces uasge of ubi-manifest that provides manifests of final content of ubi repos. Following is included in this changed:

• implemented a simple client for ubi-manifest servivce with task poller
• integrated usage of ubi-manifests in the ubipop workflow
• added required cli option --ubi-manifest-url
• tests were updated

There is still old unused code - it will be cleaned in subsequent PRs.

[codecov[bot]]

Codecov Report

Merging #179 (521a11a) into master (3a3bdb8) will increase coverage by 0.68%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #179      +/-   ##
==========================================
+ Coverage   95.72%   96.41%   +0.68%     
==========================================
  Files           5        7       +2     
  Lines         843     1004     +161     
==========================================
+ Hits          807      968     +161     
  Misses         36       36              

Impacted Files	Coverage Δ
ubipop/__init__.py	93.89% <100.00%> (+0.18%)	:arrow_up:
ubipop/cli.py	95.74% <100.00%> (+0.09%)	:arrow_up:
ubipop/ubi_manifest_client/client.py	100.00% <100.00%> (ø)
ubipop/ubi_manifest_client/models.py	100.00% <100.00%> (ø)

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[rbikar]

Note: Jenkins CI is NOT expected to work at this stage as it requires update to integration tests and environment.