Remove obsolete 'bin/st2-check-license'

[arm4b]

The project ships /~https://github.com/StackStorm/st2/blob/master/st2common/bin/st2-check-license which is irrelevant now, considering ongoing EWC features integration in the st2 core.

The task is to find all the places: /~https://github.com/search?q=org%3AStackStorm+st2-check-license&type=code and remove the st2-check-license scripts.

This is an easy good first issue for someone willing to start contributing and exploring the st2 system.
Bonus points to find other obsolete, outdated, irrelevant scripts in st2 core.
Help wanted!