update ignore pattern for built-in pages "templates"

ignore autotools stuff in etc/ too

kill compile_flags.txt

tweak the ignore list

move some unicode-related code in u/

generalize some ignore patterns

add about:crash

ignore pages/about_new.gmi (autogenerated from .in)

move built-in pages to pages/*.gmi

behold the great emoji-matcher!

move the list of cmd to its own file

link the parser in the build and: * add some flags * document them * move the customizable stuff to defaults.c

ignore dist tarballs

ignore compile_flags.txt

switch to phos_uri Initially I took the IRI parser from gmid, stripped of the UTF-8 things and transformed back into a URI parser. Then I've added some functions to resolve URIs, but it wasn't enough. gmid parser is aimed at servers, and so it doesn't handle very well relative links. This makes use of the libphos uri parser, which was coded to follow the RFC more strictly, and to fully support all kinds of URIs. It'll need to be expanded in the future and be improved for sure