feat: install wizard on first launch (#1977)

* Login form loading

* add first install middleware and settings

* updates

* Login form loading

* add first install middleware and settings

* updates

* only set first install when superuser is created

* refactor first install

* only show if first install

* cleanup

* set password

* update calls

* login superuser on first install

* fix

* fixup!

* fixup!

* fixup!

* fixup!

* fixup!

* last fixup!

* fix mypy and prettier CI errors

* disable first install

* add random super user

* set first install after startup

* remove user id from form

* Update lnbits/core/views/auth_api.py

Co-authored-by: Vlad Stan <stan.v.vlad@gmail.com>

* Update lnbits/core/views/auth_api.py

Co-authored-by: Vlad Stan <stan.v.vlad@gmail.com>

* Update lnbits/middleware.py

Co-authored-by: dni ⚡ <office@dnilabs.com>

* addressing Vlad's comments

* remove super user

* move to transient settings

* fix: show `first_install` page even after a server restart

* fix: do not add `user_id` in the auth token

* fix: `make check` errors

* fix: `username` is not optional for `UpdateSuperuserPassword`

* feat: nicer error message

---------

Co-authored-by: dni ⚡ <office@dnilabs.com>
Co-authored-by: Tiago Vasconcelos <talvasconcelos@gmail.com>
Co-authored-by: Vlad Stan <stan.v.vlad@gmail.com>

lnbits/settings.py

@@ -390,6 +390,7 @@ class TransientSettings(InstalledExtensionsSettings):
     #  - are not read from a file or from the `settings` table
     #  - are not persisted in the `settings` table when the settings are updated
     #  - are cleared on server restart
+    first_install: bool = Field(default=False)
 
     @classmethod
     def readonly_fields(cls):