Add special directory detection for TPB and Omnibus

[gerrewsb]

In Komga we have to option to detect OneShots by setting the One-Shots directory option in the library options. It would be nice if we could also set this for TPB and Omnibus. Right now i put TPB's and Omnibi in a _oneshot folder so they get picked up as a single issue in Komga instead of a folder with a single issue. But this means it has the subtitle One-Shot under the title. It would be nicer if the subtile would be Trade Paper Back or Omnibus.

[gotson]

It's still a one shot though, ie a book that is its own series/ Komga does not care about what content you store. People storing manga argue that Book should be name Chapter.