Proposal : Rename doc-install to doc-admin

[ZeikoFr]

To be more focused on the purpose of each documentation I think we should rename this doc in doc-admin.

This change would make the 3 docs repository with the same name as they are in the project page documentation :

And it will allow everyone to add a lot of other important information about managing a GLPI server (it's not just install and update) that are currently only in the old documentation.

I think we should follow the path of the nextcloud documentation that as three distinct manual :

Any opinion about this ?

[cedric-anne]

Indeed, this documentation contains more than just installation/update instructions. Changing the repository URL should not annoy too many people, given the few contributions outside of GLPI core developers.