Summary:
Make InstallNodeAgent independent self sufficient task. InstallNodeAgent can now both be used with YNP and with other standalone sites, e.g., NodeAgentEnabler.
Also, moves install python/pip command to YNP for CSP's

Minor cleanup in YNP for CSPs

Test Plan:
Manually created the universe with YNP.
iTest pipeline

Reviewers: nsingh, anijhawan

Reviewed By: nsingh

Subscribers: yugaware

Differential Revision: https://phorge.dev.yugabyte.com/D41788