* Add session context outbounds as slice
slice is needed for dialer proxy where two outbounds work on top of each other
There are two sets of target addr for example
It also enable Xtls to correctly do splice copy by checking both outbounds are ready to do direct copy
* Fill outbound tag info
* Splice now checks capalibility from all outbounds
* Fix unit tests
Android client prepares an IP before proxy connection is established. It is useful when connecting to wireguard (or quic) outbound with domain address. E.g. engage.cloudflareclient.com:2408
* Increase some tls test timeout
* Fix TestUserValidator
* Change all tests to VMessAEAD
Old VMess MD5 tests will be rejected and fail in 2022
* Chore: auto format code
