Restructure error handling for semantics

[TheGupta2012]

Summary of changes

Fixes #149

• We want to have a better way to emit errors to the user when doing semantic analysis. Currently we stop processing after an error is encountered, which may not be the best strategy for error discovery
• Tasks -
  • Define warning and fatal errors
  • Strategy for warnings
  • Strategy for fatal errors
  • Error threshold
  • Tests

[codecov]

Codecov Report

Attention: Patch coverage is 92.42424% with 5 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
qbraid_qir/qasm3/visitor.py	91.11%	4 Missing ⚠️
qbraid_qir/qasm3/exceptions.py	92.85%	1 Missing ⚠️

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