Cockpit: add HotSync interface

[federicoballarini]

Create HotSync interface for Cockpit UI.

See also
https://community.nethserver.org/t/hotsync-cockpit/

[DavidePrincipi]

Thank you for the HotSync UI contribution! As said in the community thread, we're moving nethserver-hotsync to NethForge. Please wait until Thursday for a complete update of the nethserver-hotsync status.

[gsanchietti]

The HotSync has been officially moved to the Forge. @federicoballarini is the new maintainer.

[edospadoni]

We found a vulnerable dependency in this repository. Execute:

cd ui && npm audit fix

to upgrade npm modules version and fix ui vulnerabilities