feature: Add delay and barrier for circuits

[rmshaffer]

Issue #, if available:

974

Description of changes: Starting with the changes from #993 and performing the additional work required to merge to main.

The biggest outstanding items are:

• [ ] Both Barrier and Delay should likely inherit from CompilerDirective rather than Gate, since they are instructions that affect the compilation of a program rather than the quantum state. See this comment thread.
• [ ] Significant duplication between the new DurationGate class and the existing AngledGate class that should be reduced. See this comment thread.
• [ ] Calling barrier() with no qubit arguments should add a barrier on all qubits (i.e., barrier; in OpenQASM). See this comment thread.

Testing done: tox

Merge Checklist

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.00%. Comparing base (90f9395) to head (b1c414a).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1002 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 135 136 +1 Lines 8949 9038 +89 Branches 2011 2029 +18 ========================================= + Hits 8949 9038 +89 ```

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