Adds delete user functionality in admin panel #86 (#110)

* #86 Adds delete user functionality in admin panel

* Removes unnecessary code

* Prevents current user from deleting itself

server/prisma/models/client.prisma

@@ -9,7 +9,7 @@ enum ClientCapabilities {
 model Client {
     id     String @id @default(uuid())
     userId String
-    user   User   @relation(fields: [userId], references: [id])
+    user   User   @relation(fields: [userId], references: [id], onDelete: Cascade)
 
     capabilities ClientCapabilities[]