the plugin has been abandoned, I have moved it to ai-mu-plugins for the moment.

Closes #17

added noblogs/themes-misc as a dependency, and removed the corresponding theme patches.
This themes are not on wordpress.org anymore, so they will not be updated from upstream,
and thus we have to keep them in our own repo (but there is no need to separate patches
from upstream).

We might want to consider whether to keep them or remove them in the future.

This commits gets rid of the extra external directory to unpack mu-plugins.
They are instead directly extracted into wp-content/mu-plugins/{name}/, and then the relevant files are copied
(via the drop-in mechanism) to wp-content/mu-plugins/. This leaves spurious directories with undeeded files (readme, composer conf, etc.),
but they should be harmless.

the Drop-in mechanism does not need to specify a file-name, in which case it copies all files (excluding readme.txt and similars). Slightly less stuff to write in this case: plugins which declare themselfs to be mu-plugins will be handled automaticaly, the ones which do not have to be listed twice.

More-privacy-option plugin actually ships with other files (translations), so it should not be considered a mu-plugin, but installed network wide as a regular plugin.

KaTeX is a LaTeX plugin and js library which should be ligher, smaller, faster, but less complete than MathJax (which is what we were using so far). It might be worth to try it as an alternative (I don't think there is heavy usage of Latex on noblogs).

Closes #6