- This prevents the "no available updates" pop-up from showing up when it's an automatic check. Thank you @chenshaoju for your feedback.
- Checking pre-release checks in the menu would work on the current run now.

- Infrastructure: use one HttpClient instance throughout the lifecycle
- Version update: rewrite the update service and add update prompt window
- Server sharing: add copy link button
- Dependencies: add ReactiveUI.Events.WPF, ReactiveUI.Fody, ReactiveUI.Validation, WPFLocalizeExtension, MdXaml

- Validate geosite group configuration
- Reset to default if specified group doesn't exist
- Regenerate pac.txt on version update (can be turned off)
- Cleanup of `Configuration` to separate loading logic and processing logic

# Conflicts:
#	shadowsocks-csharp/Controller/Service/UpdateChecker.cs
#	shadowsocks-csharp/Controller/System/ProtocolHandler.cs
#	shadowsocks-csharp/Program.cs
#	shadowsocks-csharp/packages.config
#	shadowsocks-csharp/shadowsocks-csharp.csproj

target set to net core 3.1
managed cryptography implementation, drop x86 only
few modify to make new target working

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>