fix command of systemctl enable --now mtg, in case of old systemd version can not support

• Allow time drift on hosts (openvz vps often seen)

fixes support on arm system. Tested on oracle cloud arm machines. Oracle Linux 7 Arm64/aarch64.

fix bug while fresh install #10 #11 #12

clearer code promotions

bin deleted for a serious bug #10 #11 #12

support offline install mode

• Upgrade mtg binary if /etc/mtg.toml exsits
• colorize the script output

shows t.me url using mtg access /etc/mtg.toml

use default fronting domain and 443 port
fix #9