Build fix for Windows
Implement "feature disable" for Windows

fixes #7418
Implement the "variable" CLI command

fixes #7370
Add missing file

refs #7370
Add missing new-line after output

refs #7370
Remove {DAEMON,ICINGA2}_USER and {DAEMON,ICINGA2}_GROUP variables

refs #7370
Add another missing new-line

refs #7370
Implement "pki save-cert" command

fixes #7422
CLI: Add basic agent command functionality (add, remove)

Prepare for set, setup, wizard, *list.
Change repository files to .repo, rename .peer to .settings

refs #7248
refs #7255