Always finish pinned big files

# Why?

Currently if you start downloading a big file it will give up on the unreachable parts after a while (30 retry). This could be problematic for files where the seeder is not online 24/7.

# How?

Don't remove big file parts from download queue if the file is pinned.

# Problem: Garbage collection

Currently all big files larger than 20MB automatically got pinned to avoid automatic deletion and to exclude it from optional file garbage collection.

## Solution

Exclude all files from garbage collection limit and automatic deletion larger than 20MB even if it's not pinned.

# Plan

- [x] Exclude all files larger than 20MB from automatic deletion and garbage collection limit
- [x] Don't pin big files larger than 20MB automatically
- [x] Don't expire download tasks of pinned big files
- [x] Don't delete pinned files if the site owner removed it
- [ ] List of big files that deleted by the site, but still on the HDD
- [x] Modify ZeroUP to pin files on seed button click
- [x] Allow to filter to pinned files
- [x] Also list pinned and downloading optional files on "Seeding" tab of ZeroUp
- [ ] Fix initial seed number query on ZeroUp
- [ ] Fix Nan peer number of ZeroUp (no file info due 1000 limit on optionalFileList)
- [x] Reset bigfile retry number if one piece is done