✨ Add unitary matrix to gate definitions in MLIR tablegen

[taminob]

Description

Define unitary matrix definition for 1- and 2-qubit gates via MLIR tablegen.
This avoids a dependency to the dd package which already contains the gate definitions.

Required for #1182 and #1206

Checklist:

• The pull request only contains commits that are focused and relevant to this change.
• I have added appropriate tests that cover the new/changed functionality.
• I have updated the documentation to reflect these changes.
• I have added entries to the changelog for any noteworthy additions, changes, fixes, or removals.
• I have added migration instructions to the upgrade guide (if needed).
• The changes follow the project's style guidelines and introduce no new warnings.
• The changes are fully tested and pass the CI checks.
• I have reviewed my own code changes.