Improve wording / understanding of the admin screen

[lebouquetin]

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Description

This issue is related to the subject created on galae.net community space - https://community.galae.net/ui/workspaces/1/contents/thread/995

Statistics and quota may be misunderstood.

On the screenshot:

Quota : 2.3 GiB: total quota dedicated to the domain name. 2.0 GiB: quota already dedicated to mailboxes (300 MiB still available for dispatch) Statistics 3687 : number of emails 281.1 MiB : storage really used

Expected (one of or a combination of all) :

• add a help text in the headers in order to explain meaning of each value.
• add a title text on values
• add a help button + text on every field
• ...