implement sm⊗sm, tHadamard*sm, pcT⊗P"X" , pcT*tId1 , P"-Y"*sm and copy(sm) from #260

[Fe-r-oz]

Building on #259, breaking down #260 in two smaller PR. Thus, this is the first PR that implements the following:

• sm⊗sm
• tHadamard*sm
• tId1*pcT
• pcT⊗P"X"
• copy(sm)
• P"-Y"*sm

Apologies for the frustrating experience. Hopefully, everything is better now.

P.S. I have also started working on the second half, but before that, we have to introduce embed for AbstractStabilizer and Tableau which is done in (#342). This will be helpful in implementing embed(..., sm).

I am looking for your feedback. Thank you for review.

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Please address only one topic or issue per pull request! Many small PRs are much easier to review and merge than one large PR.

Before merging, all changes and new functionality should be marked in the CHANGELOG file, but feel free to just leave your CHANGELOG notes in the PR description, to avoid merge conflicts with other requests modifying that file. The maintainer will add these CHANGELOG notes for you if you do so.

Before considering your pull request ready for review and merging make sure that all of the following are completed (please keep the clecklist as part of your PR):

• The code is properly formatted and commented.
• Substantial new functionality is documented within the docs.
• All new functionality is tested.
• All of the automated tests on github pass.

If possible, keep your git history not too wild (rebase and squash commits, keep commits small and semantically separated) so that review is easier.
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[Krastanov]

This would be pretty difficult to review as is. Here are a few things that might help (do not worry about it too much if it is the first time you are experiencing this workflow, it takes a while to get accustomed to it):

• If the pull request is about finishing improvements to the non-clifford functionality #259, it should be a pull request for merging into the branch noncliff, not into the master branch like this one. In that case it would also not have the need for the complicated Merge branch 'master' into nonstab step.
• If the pull request is about adding extra interfaces as described in improvements to GeneralizedStabilizer API #260, then it probably should be done independently, not on top of improvements to the non-clifford functionality #259 (most easily, that would be after improvements to the non-clifford functionality #259 is finished)

I personally would avoid trying to merge the #260 API improvements (what this PR seems to be) until #259 itself is finished (it currently has a buggy implementation).