Fix --list-themes and colorized User-Agent

[ldionmarcil]

Hi, two bug fixes in this PR.

1. the --list-themes was broken because of a missing module name. See error below

$ ruby /Users/louis.dionmarcil/Tools/autochrome/autochrome.rb --list-themes
Ignoring http_parser.rb-0.8.0 because its extensions are not built. Try: gem pristine http_parser.rb --version 0.8.0
Traceback (most recent call last):
        7: from /Users/louis.dionmarcil/Tools/autochrome/autochrome.rb:102:in `<main>'
        6: from /Users/louis.dionmarcil/Tools/autochrome/autochrome.rb:95:in `parse_options'
        5: from /Users/louis.dionmarcil/.rbenv/versions/2.6.0/lib/ruby/2.6.0/optparse.rb:1553:in `order'
        4: from /Users/louis.dionmarcil/.rbenv/versions/2.6.0/lib/ruby/2.6.0/optparse.rb:1562:in `order!'
        3: from /Users/louis.dionmarcil/.rbenv/versions/2.6.0/lib/ruby/2.6.0/optparse.rb:1568:in `parse_in_order'
        2: from /Users/louis.dionmarcil/.rbenv/versions/2.6.0/lib/ruby/2.6.0/optparse.rb:1568:in `catch'
        1: from /Users/louis.dionmarcil/.rbenv/versions/2.6.0/lib/ruby/2.6.0/optparse.rb:1582:in `block in parse_in_order'
/Users/louis.dionmarcil/Tools/autochrome/autochrome.rb:81:in `block (2 levels) in parse_options': uninitialized constant ProfileBuilder (NameError)

Fixed it in commit 08be53b.

2. The User-Agent headers were not properly sending the profile's colour (ie User-Agent: Mozilla... autochrome/red). This was due to the profile Bookmarks not being generated properly, and the User-Agent relying on Bookmarks to get the current profile's colour. I fixed the structure of data/bookmarks.yaml by adding the (seemingly) now necessary "synced" JSON key.