add ACME domain editing

add ACME domain editing

Same deal, however, here the PVE code is has a little bug
where changing the plugin type of a domain makes it
disappear, so this also contains some fixups.

Additionally, this now also adds the ability to change a
domain's "usage" (smtp, api or both), so similar to the
uploadButtons info in the Certificates panel, we now have a
domainUsages info. If it is set, the edit window will show a
multiselect combobox, and the panel will show a usage
column.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>