Modpack support (#60)

* Modpack support

* Finish feature

* Tauri errors fix (#61)

* async impl

* working

* fmt and redundancy

* moved ? to if let Ok block

* Finish modpacks support

* remove generated file

* fix compile err

* fix lint

* Fix code review comments + forge support

---------

Co-authored-by: Wyatt Verchere <wverchere@gmail.com>

theseus_gui/src/helpers/pack.js

@@ -0,0 +1,16 @@
+/**
+ * All theseus API calls return serialized values (both return values and errors);
+ * So, for example, addDefaultInstance creates a blank Profile object, where the Rust struct is serialized,
+ *  and deserialized into a usable JS object.
+ */
+import { invoke } from '@tauri-apps/api/tauri'
+
+// Installs pack from a version ID
+export async function install(version_id) {
+  return await invoke('pack_install_version_id', version_id)
+}
+
+// Installs pack from a path
+export async function install_from_file(path) {
+  return await invoke('pack_install_file', path)
+}