Uses all of my CPU with Library

When the script is still in the first few minutes of operation, I see a CPU percentage of 80-100% on a single core.
```
 93.2% CPU - 4:20.45 - python ./plex_debrid/main.py --config-dir /config
```
Later on, after a day or so, many more `plex_refresh.py` processes being spawned, using up the rest of my cores until the entire CPU is saturated. 
