Only scrubbing "content" leads to differences between
"content" and "contentMap" eventhough the latter should
ideally match the former exactly for the primary language’s entry.
While ideally, for locally generated posts there should be no difference
between applying the scrubber or not, as it turns out automatically
generated attachment links didn't match the form expected by our default
scrubber.
Currently Akkoma never uses nor exposes the value of contentMap entries,
thus this oversight was harmless wrt to safety and at most pertubed
the language detection for our posts perfomed by remote servers.
Fixes: https://akkoma.dev/AkkomaGang/akkoma/issues/928
Related to #85
Everything should now be configured at runtime, with the exception of
the `Pleroma.HTML` scrubbers (the scrubbers used can be
changed at runtime, but their configuration is compile-time) because
it's building a module with a macro.
