build-sys: meson: Allow building only the daemon
This is continuation of daemon/client split on top of !657 (closed) as agreed with @leio
- replace meson option
daemon-only
with inverse optionclient
- clean up remaining tests to fall under 'daemon' and 'client'
- rearrange dependency detection to make client/daemon separation more clear
- fix bash completion to not install same file twice when client and daemon are built separately
Edited by Igor Kovalenko