[Libguestfs] [PATCH 0/7] Support Windows BitLocker (RHBZ#1808977).

These commits, along with the associated changes to common: https://www.redhat.com/archives/libguestfs/2020-March/msg00286.html support the transparent decryption and inspection of Windows guests encrypted with BitLocker encryption. To do the BitLocker decryption requires cryptsetup 2.3.0 (although cryptsetup 2.3 is not required for existing LUKS use). It also requires a new-ish Linux kernel, I believe 5.3+ This starts by adding new APIs cryptsetup-open and cryptsetup-close. As well as dropping the "luks-" prefix, this allows specifying an optional type parameter, allowing you to select BitLocker encryption. Although also the new API does not require this parameter, and will autodetect the correct type of decryption to apply in every known case. The main work is then in updating list-filesystems and ensuring that inspection still works. This really needs but also lacks tests. See commit message of patch 1/7 for why. I believe it's impossible for us to prove unit testing right now, but hopefully this situation can improve in future. Rich.