- HttpClientHandler is not used in .NET Core 3+

# Conflicts:
#	shadowsocks-csharp/Controller/Service/UpdateChecker.cs

Optimization for MD5

🏗 Use `dotnet publish` for artifacts generation

- Cleanup of build script
- Cleanup of publish profiles

# 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

Code optimization for SodiumIncrement

Fix improperly parsed remark section

v5 udp fix

Always sip002

🔙 Backport 2c15276 from v5/master to master

🔐 Add Sha256sum verification for GeoSite db + other fixes and cleanup

- Compared to 2c15276: changed socketsHttpHandler to HttpClientHandler due to legacy .NET Framework
- Use System.Net.Http.HttpClient for GeositeUpdater
- New update check mechanism: first download checksum and compare, only download GeoSite DB on different checksum
- Verifiy downloaded GeoSite DB by comparing sha256sum before committing the change

- Removed some legacy compatibility code from Program.cs as we are not using .NET Framework.
- Changed CurrentDirectory detection method so that Self-Contained .exe can have its configuration files in the same directory as the .exe instead of in the temporary folder.

- Use System.Net.Http.HttpClient for GeositeUpdater
- New update check mechanism: first download checksum and compare, only download GeoSite DB on different checksum
- Verifiy downloaded GeoSite DB by comparing sha256sum before committing the change