Add GitHub client code into the codebase to fetch the latest release from the github

[aniruddha2000]

/kind feature

Describe the solution you'd like
Have the code to fetch release assets from GitHub so we don't have to specify the --github-release flag every time.

Anything else you would like to add:
[Miscellaneous information that will assist in solving the issue.]

Environment:

• csmctl version: (use kubectl version)