Import page 'Who is Allowed to Modify Which Packages' from wiki
    
    The page was categorized under "Package Maintainers" in wiki,
    but actually contains policies that are decided by FESCo.
    Thus, the correct location of the page
    is in the FESCo documentation site.
    
    Updating links to the wiki page to cross references
    led to applying semantic line breaks to a single line paragraph
    in the Provenpackager Policy page.
    This led to small changes in wording, too,
    because the original was slightly hard to read.
    There was no intent to change the meaning.