feat(frontend): added user deletion to the user list

also includes small updates to the api to prevent administrators from being deleted, as well as
migrations to cascade deletions to requests the users made

fixes #348

server/entity/MediaRequest.ts

@@ -36,10 +36,18 @@ export class MediaRequest {
   })
   public media: Media;
 
-  @ManyToOne(() => User, (user) => user.requests, { eager: true })
+  @ManyToOne(() => User, (user) => user.requests, {
+    eager: true,
+    onDelete: 'CASCADE',
+  })
   public requestedBy: User;
 
-  @ManyToOne(() => User, { nullable: true, cascade: true, eager: true })
+  @ManyToOne(() => User, {
+    nullable: true,
+    cascade: true,
+    eager: true,
+    onDelete: 'SET NULL',
+  })
   public modifiedBy?: User;
 
   @CreateDateColumn()