XTLS support

[nihil-admirari]

Is your feature request related to a problem? Please describe.
Both Wireguard and IKE are easily blocked, sometimes at state level: #1586, #1588, #1643. XTLS avoids detection and blocking by masquerading as plain HTTPS.

Describe the solution you'd like
A automated script for configuring XTLS with security best practices.

Describe alternatives you've considered
Wading through https://github.com/xtls/Xray-examples.