Allow custom filters in `@extrakto_filter_order` about extrakto

[laktak]

Thanks @marcdeop!

@qstrahl can you test if it works for you? I forgot that we still have a sanitize_modes_list check ... that will have to be either removed or updated before this works. I'll let you know.

[laktak]

Not sure if @marcdeop is still interested - he did fix this in #103 but that PR was too large to merge

[qstrahl]

Ah, missed that one - thanks for pointing me in that direction. I'll take a look at the PR and see if I can't pull out the relevant parts

[marcdeop]

Hopefully this is fixed (or at least improved) by #111

[laktak]

@qstrahl it works now

[qstrahl]

@laktak Awesome! Thank you so much, and you too @marcdeop !