- 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

- Remove StringEx.CS
- Update all dependencies
- Eliminate all warnings

Always sip002

- 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

also with some i18n update

Using NLog as the logger

No wrapper is used since we would use NLog for some time.
Currently the UI is not fully ready to select all log levels.

Fix #2782

https://github.com/shadowsocks/shadowsocks-windows/issues/2657

Support Windows 10 1903 Light Theme

But Fix Support Windows 10 1903 Dark Theme

Support Windows 10 1903 Light Theme

Fixed bug of #2379 pullrequestreview-254461303
Redundant paintings when user move mouse on the icon, pixel by pixel.

Move GetWindows10SystemThemeSetting() to Util.cs
WindowsThemeMode use enum
Status var windowsThemeMode rename to windowsThemeMode
Used `if else` to replace `switch case`
Delete legacy commint (Some code).
Increase contrast for icon.

Add new hints and fixed some old interaction bugs

Support Windows 10 1903 Light Theme (Menu icon color)

Because the splash is already on the target display, the target rect doesn't need to calculate with the screen position.

"Allow Clients from LAN" --> "Allow other Devices to connect"

* Rename variable 'traffic' to 'trafficPerSecondQueue' and 'trafficInfoQueue'

* Remove class QueueLast<T> by using linq Queue.Last()

* Slight changes, such as rename, move several variables from function domain to class domain to improve performance.
Logic remains the same.

* Update the logic of copying queue from Controller to View.

* Move the TrafficInfo declaration into LogForm class

Overwise, the VS UI designer does not work.

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