[feature] Check Assignments for Similarity

[gaocegege]

/kind feature

Describe the solution you'd like
[A clear and concise description of what you want to happen.]

we should avoid generating duplicate assignments, at least warning message should be logged

While some think that this check's scenario is rare. We do not decide if we need it.

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

[gaocegege]

cc @hougangliu @johnugeorge

[gaocegege]

/priority p3

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[andreyvelich]

/lifecycle frozen