srcfpo theme: left-align the lines in description
    
    The description texts are taken from package %descriptions, and our packaging
    guidelines specify that the text is 80-column wrapped. Centering the lines of
    the text leads to poorly-looking christmas-tree-like layout. People occasionally
    use lists and such, and this looks especially bad if the vertical alignment
    is not preserved.
    
    I think it's nice to leave the paragraph centered, but with individual lines
    left-aligned within the paragraph:
    
      Blah blah  blah  blah  blah  blah  blah  blah  blah blah blah blah
      blah  blah  blah
      blah  blah  blah  blah  blah  blah  blah  blah  blah blah blah:
      - foo
      - bar
      blah  blah  blah  blah  blah  blah  blah  blah  blah  blah  blah
    
    Tested with firefox-92.0.1-1.fc35.x86_64, chromium-93.0.4577.63-1.fc35.x86_64.
    
    Signed-off-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>