Excitation number restricted (ENR) state space implementation

[TendonFFF]

Checklist

Thank you for contributing to QuantumToolbox.jl! Please make sure you have finished the following tasks before opening the PR.

• Please read Contributing to Quantum Toolbox in Julia.
• Any code changes were done in a way that does not break public API.
• Appropriate tests were added and tested locally by running: make test.
• Any code changes should be julia formatted by running: make format.
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• (If necessary) the CHANGELOG.md should be updated (regarding to the code changes) and built by running: make changelog.

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Description

Add functionalities for ENR space, as QuTiP.

• Define EnrSpace and enr_state_dictionaries
• Define basic functions
  • enr_identity
  • enr_fock
  • enr_destroy
  • enr_thermal_dm
• Support kron
• make sure ptrace, permute, and partial_transpose doesn't support EnrSpace

[codecov]

Codecov Report

Attention: Patch coverage is 92.23301% with 8 lines in your changes missing coverage. Please review.

Project coverage is 94.05%. Comparing base (0066cdb) to head (14eb47e).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/qobj/energy_restricted.jl	92.85%	6 Missing ⚠️
src/qobj/dimensions.jl	66.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #500      +/-   ##
==========================================
- Coverage   94.12%   94.05%   -0.08%     
==========================================
  Files          50       51       +1     
  Lines        3421     3514      +93     
==========================================
+ Hits         3220     3305      +85     
- Misses        201      209       +8     

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[ytdHuang]

I will fix the error later