Specify partitions to be used instead of entire disk

[jozefmutis]

Currently the installer uses entire disk - as such it can't be installed next to existing OS like Windows, even if partitions are allocated and formatted before hand.

Installer has option to specify target partitions for /boot/efi, / (and optionally swap)

[r0b0]

Now that we are using repart to manage partitions, this should be much easier to implement.

[romangg]

IMO scope should be limited and this not implemented. Depends of course on the complexity.