Migrate frontend to yew (#56)

* Implement main logic of frontend in yew

* made duration input much better

* clean duration input code a bit up

* put config.toml.sample in right place

* integrate css

* put config.toml on .gitignore

* Delete backend/config.toml

* refactor folder structure in frontend

* clean .gitignore up

* updated yew to 0.21.0

* move tracing setup to util.rs

* format files with cargo fmt and reorder structs and impls

* Delete .idea directory

* change the submit logic to prevent page reloads in case of panics

* make copy button select text when pressing

* changes from laptop

* changes from desktop

* fix layout shift

* remove error message timer and instead remove all messages on next use of the shortener

* * switch linked-hash-set library to a more feature full one
* display a x remaining messages message when there are more then n messages

* put labels above input instead of relying on placeholder

* implement the backend checks for negative max_uses and valid_for in frontend

* ported all possible scss to stylist

* applied suggestions

.gitignore

@@ -1,9 +1,10 @@
 /target
-/config.toml
+/backend/config.toml
 /database
 /.env
 database.db
-/database.db-shm
-/database.db-wal
+database.db-shm
+database.db-wal
 .idea
-/.fleet/
+.fleet
+/frontend/dist