feat: add password reset for usermanager (#2688)

* feat: add password reset for usermanager
- add a reset_key to account table
- add ?reset_key= GET arguments to index.html and show reset form if provided
- superuser can generate and copy reset url with key to share
future ideas:
- could add send forgot password email if user fill out email address
* feat: simplify reset key
* test: use reset key
* test: add more tests
* test: reset passwords do not match
* test: `reset_password_auth_threshold_expired`

---------

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

lnbits/core/templates/users/index.html

@@ -84,6 +84,15 @@ include "users/_createWalletDialog.html" %}
                 >
                   <q-tooltip>Super User</q-tooltip>
                 </q-btn>
+                <q-btn
+                  round
+                  icon="refresh"
+                  size="sm"
+                  color="secondary"
+                  @click="resetPassword(props.row.id)"
+                >
+                  <q-tooltip>Generate and copy password reset url</q-tooltip>
+                </q-btn>
                 <q-btn
                   round
                   icon="delete"