extend Enterprise.md for app language and spellchecker

[q16marvin]

Problem Description

Under https://github.com/zulip/zulip-desktop/blob/main/docs/Enterprise.md we found a extrem cool way to give our users a default organistation when we deploy zulip as desktop client via msi. know most of our "users" cant speak english, so it would be awesome to set also app language via this enterprise.md file.

nice to have also would be options for "spellchecker" and "auto start at login"

that would be awesome :)

Thx!
Erik