Hints for backintime-qt in main

Warnings

• asv-summary-too-long
  io.github.bit_team.back_in_time.gui.metainfo.xml:14 - Backup tool for GNU Linux desktop using rsync with its hard-links feature to save storage space
  The summary text is very long, and will likely not be displayed properly everywhere. It should be <= 90 characters.
• screenshot-download-error
  Error while downloading screenshot from 'https://translate.codeberg.org/media/screenshots/bit_16to9_1280x720_general_ssh.png': URL was not found on the server.
  This might be a temporary server issue, or the screenshot is no longer available.