Fix role creation leaving new roles with zero permissions

[ShowMeMyCent]

RoleController::store had three stacked bugs that combined to make role creation silently non-functional:

• The 'super' and 'aslab' package cases were commented out in the switch statement, falling through to a default branch that reset the whole permissions accumulator to empty.
• No package guaranteed manage-profile/lms-configuration, the only permissions accepted by the /assistant route every asisten lands on after login, so roles without asisten or aslab checked could log in but were immediately blocked.
• PermissionGroupEnum::ASISTEN (the default, pre-checked package) referenced see-modul, a permission never seeded into the database and checked by no route. syncPermissions() throws on unresolvable names before writing anything, so any role including the default package ended up with zero permissions regardless of the fixes above. Removed the dead see-modul entry; ImportSqlDump.php already worked around this same bug locally, so simplified it to match.

Also gate Reverb/Echo initialization on VITE_REVERB_APP_KEY being configured, since local dev without a running Reverb server was spamming failed websocket reconnect attempts. Removed echo.js, a dead duplicate of the same unconditional Echo instantiation.