Replicate remote sequence validation locally

[HGSilveri]

When a user submits a sequence for remote execution, there are some checks that are executed only remotely. This makes it possible to have a sequence that's valid locally fail execution. To minimize the chance of this happening, we can centralize all checks within a method (in Sequence, perhaps?) that can be used to run the whole checks locally. Furthermore, this would allow us to have different backends enforce the same checks as a QPU, thus increasing the similarity of the user experience with that of remote QPU.