Adding support for TMC-Plugin discovery

[pgandigesang]

What this PR does / why we need it

This change is required to add support for TMC-Plugin discovery.

Which issue(s) this PR fixes

Fixes #3204

Describe testing done for PR

Release note

Added discovery source for TMC.
Fixed fetching artifacts over http to handle large file reads by processing chunks at a time.

PR Checklist

• Squash the commits into one or a small number of logical commits
  
• Use good commit messages
• Ensure PR contains terms all contributors can understand and links all contributors can access

Additional information

Special notes for your reviewer

[rajathagasthya]

Can you create a separate Github issue for this and link it in the PR description please?

[codecov]

Codecov Report

Merging #2950 (2302ca3) into main (254f018) will increase coverage by 0.12%.
The diff coverage is 42.50%.

❗ Current head 2302ca3 differs from pull request most recent head 92101e1. Consider uploading reports for the commit 92101e1 to get more accurate results

@@            Coverage Diff             @@
##             main    #2950      +/-   ##
==========================================
+ Coverage   45.82%   45.95%   +0.12%     
==========================================
  Files         361      391      +30     
  Lines       37642    40566    +2924     
==========================================
+ Hits        17249    18641    +1392     
- Misses      18820    20216    +1396     
- Partials     1573     1709     +136     

Impacted Files	Coverage Δ
pkg/v1/cli/artifact/http.go	0.00% <0.00%> (ø)
pkg/v1/config/defaults.go	40.00% <0.00%> (-2.31%)	⬇️
pkg/v1/config/clientconfig.go	44.55% <56.25%> (ø)
pkg/v1/cli/command/core/discovery_source.go	41.86% <100.00%> (+1.95%)	⬆️
pkg/v1/cli/catalog.go	50.51% <0.00%> (-3.44%)	⬇️
addons/controllers/machine_controller.go	65.65% <0.00%> (-3.04%)	⬇️
pkg/v1/tkg/tkgpackageclient/package_update.go	83.57% <0.00%> (-1.43%)	⬇️
pkg/v1/tkg/managementcomponents/helper.go	91.89% <0.00%> (-0.22%)	⬇️
pkg/v1/cli/cmd.go	0.00% <0.00%> (ø)
... and 52 more

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[giri-varma]

LGTM @pgandigesang! Thanks for making the change

[anujc25]

This PR needs rebase. @pgandigesang Can you please help with the rebase as some of the code base has moved to cli/runtime go module.

[github-actions]

Cluster Generation A/B Results:
https://storage.googleapis.com/tkg-clustergen/2950/20220902202229/clustergen.diff.txt
Author/reviewers:
Please review to verify that the effects on the generated cluster configurations are exactly what the PR intended, and give a thumbs-up if so.

[github-actions]

Cluster Generation A/B Results:
https://storage.googleapis.com/tkg-clustergen/2950/20220902204949/clustergen.diff.txt
Author/reviewers:
Please review to verify that the effects on the generated cluster configurations are exactly what the PR intended, and give a thumbs-up if so.

[anujc25]

I am confused why this commit 4cc3008 and changes related to this commit is shown as part of this PR? cc @pgandigesang

[anujc25]

There is some issue with the rebase as some additional changes are shown as diff with this PR. But otherwise changes looks good.

[anujc25]

Changes looks good.

[giri-varma]

Looks good to me!