For SerenityOS, we parse emoji metadata from the UCD to learn emoji
groups, subgroups, names, etc. We used this information only in the
emoji picker dialog. It is entirely unused within Ladybird.
This removes our dependence on the UCD emoji file, as we no longer
need any of its information. All we need to know is the file path to
our custom emoji, which we get from Meta/emoji-file-list.txt.
This adds an option to only detect emoji that should always present as
emoji. For example, the copyright symbol (unless followed by an emoji
presentation selector) should render as text.
Parse emoji from emoji-serenity.txt to allow displaying their names and
grouping them together in the EmojiInputDialog.
This also adds an "Unknown" value to the EmojiGroup enum. This will be
useful for emoji that aren't found in the UCD, or for when UCD downloads
are disabled.
According to TR #51, the "best definition of the full set [of emojis] is
in the emoji-test.txt file". This defines not only the emoji themselves,
but the order in which they should be displayed, and what "group" of
emojis they belong to.
