Adding --no-chown was a mistake. This reverts most of commit efaef3b8
"commit: move --no-chown as commit option from 'add'"

Instead add and use --usermode intended to be used at --initdb time.
After database creation, usermode is determined based on the installeddb
file owner being root or non-root.

Move the current no-chown functionality under the --usermode and
prepare things so usermode functionality can be further extended.

Also, per documentation, --usermode is never enabled automatically.

Fixes #10954 and #10977