Fixes #7072: Support more OpenQASM 2.0 gates from qelib1.inc (#7377)

Added OpenQASM gates 

- c3sqrtx
- c3x
- c4x
- cp
- cu
- csx
- p
- rc3x
- rccx
- u
- u0

Added tests for unitary consistency for the supported gates.

Fixes #7072

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Co-authored-by: Michael Hucka <mhucka@caltech.edu>

Author: ACE07-Sev