adding Commutators, Anticommutator, Daggers

[apkille]

Defined constructors for bra, product of operators, commutator, anti commutator, and dagger. Also added scaling and a few simplification rules.

[Krastanov]

I left a couple of minor comments, nothing to interesting, and you might have already been thinking about some of these things.

I will convert this to a draft. When it is ready for review and it has all tests pass, just convert it back and request a review.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 63.09524% with 62 lines in your changes missing coverage. Please review.

Project coverage is 62.78%. Comparing base (8a75466) to head (af3c073).

Files	Patch %	Lines
src/QSymbolicsBase/predefined.jl	51.92%	25 Missing :warning:
src/QSymbolicsBase/basic_ops_homogeneous.jl	61.22%	19 Missing :warning:
src/QSymbolicsBase/literal_objects.jl	57.14%	9 Missing :warning:
src/QSymbolicsBase/basic_ops_inhomogeneous.jl	75.00%	5 Missing :warning:
src/QSymbolicsBase/rules.jl	80.00%	3 Missing :warning:
src/QSymbolicsBase/QSymbolicsBase.jl	90.90%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #40 +/- ## ========================================== + Coverage 54.70% 62.78% +8.07% ========================================== Files 14 15 +1 Lines 446 575 +129 ========================================== + Hits 244 361 +117 - Misses 202 214 +12 ```

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[apkille]

I updated functionalities of (anti)commutator and dagger. Also added operator properties (hermitian, unitary, and commutative) and wrote corresponding simplification rules, which are all tested. I added doctests as well for basic operations.

[Krastanov]

Woohoo!

[apkille]

Excellent! 😁