install_arch: skip UEFI partition on cloud servers

The need for UEFI booting originates from dedicated server and it does not benefit cloud servers. It therefore makes sense to skip it on them.

requested review from @gromit and @klausenbusk

added 11 commits

• 455c7782...542af5f0 - 10 commits from branch master
• 32a89708 - install_arch: skip UEFI partition on cloud servers

Compare with previous version

mentioned in commit 040a7838

merged manually