Allow tika to generate documents with 10M characters

The default limit of characters parsed by Tika is 100k characters,
this could result in some large documents (thesis, etc.) being
truncated.
The limit is now 10M and should be perfect for every kind of document.
A limit has to be set to avoid PDF bombs etc.
Tika parsers shouldn't be provided at runtime

Tika parsers aren't supposed to be provided by any other project.
It seems that 50eed3f6 introduced this unwillingly.
Merge branch 'master' into search-1.5.x