- Fixed KeyError in execute_in_tab
- Changed the plugin process dispatch method, this *should* fix that annoying server hang issue.

- Added retry logic to the QuickAccess tab fetching in the method call listener.
- Added exception handling, in case a plugin method returns something that can't be serialized as JSON.
- Changed a few log calls from info to debug to prevent spam
- Added a filter for asyncio base_event log records, since they get spamy and don't provide any useful info most of the time. This can be turned off with the LOG_BASE_EVENTS envar.

* 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>