Callsigns (#37)

* Plugin callsigns, filechangehandler thread bug fix, plugin file perms

- Plugins are now assigned a callsign (a random string), which they use for all internal identification, like resource fetching and method calls. This is to ensure that plugins only access their own resources and methods.
- Made FileChangeHandler send off events to a queue, that is then consumed by the Loader, instead of calling import_plugin on its own, since that caused weird issues with the event loop and the thread watchdog is using.
- Plugins are now owned by root and have read-only permissions. This is handled automatically.

* Improved general look and feel of plugin tab

* Make all plugin entries have the same padding between them

* Make "No plugins installed" text look the same as "No new notifications"

Co-authored-by: WerWolv <werwolv98@gmail.com>

requirements.txt

@@ -1,4 +1,3 @@
 aiohttp==3.8.1
 aiohttp-jinja2==1.5.0
-watchdog==2.1.7
-multiprocess==0.70.12.2
+watchdog==2.1.7