What exactly does:
"Password Management Policies" plugin
Can I install them and if I wanted, also unistall them without any issues ?
More information about the plugin is here.
The Password Management Policies plugin allows helpdesk Administrators to enforce custom requirements for Agents’ and Users’ passwords in the helpdesk.
Unfortunately, I have never used it so I cannot offer you more guidance on it beyond regurgitating what's on that page at this time.
(I should really rectify that.)
At the page you pointed me there is quite handy youtube video