resolve conjugation flags in strided implementations

[Jutho]

Possible implementation to resolve all conjugation flags by adding them to the StridedView construction phase, before the actual strided implementation is defined. I think the resulting code is actually somewhat cleaner as well. Comments are welcome, in particular from @lkdvos and @leburgel .

[lkdvos]

I think this does look good indeed, I'm happy that it's non-breaking too!

I would maybe add a comment before the if-splits explaining that it is type-stability thing, and as a reminder to not get rid of them.

Also, could you maybe double-check that the flag2op function was not being used in the extensions, or in tensorkit before removing it? Technically it has never been indicated as public API so we can remove it without having a breaking version, but it might be a useful function to have anyways.

[Jutho]

That's quick :-).
It's not used in the extensions, but I will indeed check TensorKit.

Unfortunately, the problem is not yet solved, since now makeblascontractable is type-unstable. It either returns the original StridedView, with the conjugation flag already in there, or it creates a new permuted copy, that is then not conjugated. However, that can be worked around by also making the new copy inherit the conjugation flag of the original one, so there will be another commit.

[leburgel]

Tried it out quickly on the original problem, looks perfect to me. Thanks for the quick fix!