add ssconf support

[pmoieni]

this PR adds support for ssconf transport URL to Outline CLI. I was not sure what to do with the prefix field so just left it untouched. I was not able to test the implementation either.

OutlineVPN CLI (experimental) [INFO] 2024/08/25 15:12:11 updated global IPv6 support: false [INFO] 2024/08/25 15:12:11 updated global IPv6 support: true [ERROR] 2024/08/25 15:12:11 failed to create OutlineDevice: failed to create TCP dialer: failed to decode host string [ss:///redacted/@/redacted/:8080]: illegal base64 data at input byte 2

using the official access keys I get the above error. no such issue while using ssconf key:

OutlineVPN CLI (experimental) [INFO] 2024/08/25 15:58:38 updated global IPv6 support: false [INFO] 2024/08/25 15:58:41 remote server cannot handle UDP traffic, switch to DNS truncate mode. [INFO] 2024/08/25 15:58:41 routing traffic from 10.233.233.1 to 10.233.233.2/32 through nic 9 [INFO] 2024/08/25 15:58:41 routing traffic via gw 10.233.233.2 through nic 9... [INFO] 2024/08/25 15:58:41 ip rule 'from all not to /redacted/ via table 233' created

but it doesn't seem to establish any kind of connection at all

OS: OpenSuse Tumbleweed