Create methods such as `qr_full!!` to disambiguate input handling

[kshyatt]

Idea is to support qr_full!(A, alg) which creates QR internally, and then a qr_full!!(A, QR, alg) that is "fully" inplace.

We will need to write some new AD rules for these.

[kshyatt]

cc @lkdvos if you want to flesh this out a bit