refactor: Proxy and cache avatar images (#907)

* refactor: proxy and cache user avatar images

* fix: extract keys

* fix: set avatar image URL

* fix: show the correct avatar in the list of available users in advanced request

* fix(s): set correct src URL for cached image

* fix: remove unexpired unused image when a user changes their avatar

* fix: requested changes

* refactor: use 'mime' package to detmerine file extension

* style: grammar

* refactor: checks if the default avatar is cached to avoid creating duplicates for different users

* fix: fix vulnerability

* fix: fix incomplete URL substring sanitization

* refactor: only cache avatar with http url protocol

* fix: remove log and correctly set the if statement for the cached image component

* fix: avatar images not showing on issues page

* style: formatting

---------

Co-authored-by: JoaquinOlivero <joaquin.olivero@hotmail.com>

server/job/schedule.ts

@@ -227,6 +227,9 @@ export const startJobs = (): void => {
       });
       // Clean TMDB image cache
       ImageProxy.clearCache('tmdb');
+
+      // Clean users avatar image cache
+      ImageProxy.clearCache('avatar');
     }),
   });