Simplify description?

[alexAubin]

Problem

Description should be kept concise (and especially try to avoid starting with "$app is..."). They are meant to be displayed on cards like here https://yunohost.org/apps or catalog in the webadmin

Solution

• Simpler description

PR Status

• [X] Code finished.
• [ ] Tested with Package_check.
• [ ] Fix or enhancement tested.
• [ ] Upgrade from last version tested.
• [ ] Can be reviewed and tested.