Revert "Fix: dirty hack for in-game DNA export."

This reverts commit bbc5a6094fd2aebc6e695aac34b0ab96d5bb6377.
Smoother IGB experience.
Proof of concept: filter loadouts by flyability.

The code is fairly ugly as it creates one Sphinx attribute per skill,
but it works.
Prerequisite refactoring

Also fixes "required by" lies (for example with Afterburner III and a
fit containing a T2 AB, the mastery section says "Required by 10MN
Afterburner II, High Speed Maneuvering").
Remove debug statement I missed when cleaning up
Merge branch 'prereqs-refactor' into experimental-prereqs-in-search-index

Conflicts:
	inc/fit-db.php
Dynamically generate sphinx.conf.

Allows us to use absolute paths for less friction between various
distribution configurations of Sphinx paths.

Also, renamed the `index.*` files to `loadouts.*`.

Only make attributes for skills that actually are prerequisites of
things that can be fitted.
Merge branch 'experimental-prereqs-in-search-index' into staging

Conflicts:
	src/md/changelog.md