nixos/aria2: add release note for 'rpcSecretFile'

- `nitter` requires a `guest_accounts.jsonl` to be provided as a path or loaded into the default location at `/var/lib/nitter/guest_accounts.jsonl`. See [Guest Account Branch Deployment](https://github.com/zedeus/nitter/wiki/Guest-Account-Branch-Deployment) for details.

- `services.aria2.rpcSecret` has been replaced with `services.aria2.rpcSecretFile`.

  This was done so that secrets aren't stored in the world-readable nix store.

  To migrate, you will have create a file with the same exact string, and change

  your module options to point to that file. For example, `services.aria2.rpcSecret =

  "mysecret"` becomes `services.aria2.rpcSecretFile = "/path/to/secret_file"`

  where the file `secret_file` contains the string `mysecret`.

- Invidious has changed its default database username from `kemal` to `invidious`. Setups involving an externally provisioned database (i.e. `services.invidious.database.createLocally == false`) should adjust their configuration accordingly. The old `kemal` user will not be removed automatically even when the database is provisioned automatically.(https://github.com/NixOS/nixpkgs/pull/265857)

- `inetutils` now has a lower priority to avoid shadowing the commonly used `util-linux`. If one wishes to restore the default priority, simply use `lib.setPrio 5 inetutils` or override with `meta.priority = 5`.