Hints for portfolio-filemanager in main

Hints

• asv-description-first-para-too-short
  dev.tchx84.Portfolio.metainfo.xml:39 - A minimalist file manager for those who want to use Linux mobile devices.
  The first `description/p` paragraph of this component might be too short (< 80 characters). Please consider starting with a longer paragraph to improve how the description looks like in software centers and to provide more detailed information on this component immediately in the first paragraph.
• asv-developer-name-tag-deprecated
  dev.tchx84.Portfolio.metainfo.xml:134 -
  The toplevel `developer_name` element is deprecated. Please use the `name` element in a `developer` block instead.