Upgrade to v5.1 - Changes to DI, Logger; CefSharp, .NET 5 Support

[mattkol]

With impending release of .NET 5, feedbacks and some issues raised, I want to highlights some proposed improvement we are making. It is not a major version change as it won't change that much of the current flow.

Comments are welcome.

Planned/implemented

• .NET 5 ready.

• CefSharp support - https://github.com/chromelyapps/CefSharp

• CefGlue - from v83 requires C# 8 - so a minimum of .NET Standard 2.1 is required. .NET Standard 2.0 support is deprecated.

• Merge Chromely.CefGlue into Chromely.

• Caliburn.Light Container is replaced by .NET Extensions Dependency Injection.
  This will include other .NET Extensions patterns and utilities like
  - Configuration
  - Logging

• Optional configuration file - chromelyconfig.json will be discontinued it will use a lighter version to conform with .NET Extensions Configuration pattern and easily configurable/extendable by developers.

• The use of API Restful methods like "Get", "Post" gives an impression that the Chromely Renderer process is an API. Few issues have been raised on this - use of the verbs will be discontinued as it confuses developers - it is not an API, those verbs were there to help re-use url paths. This will not be used anymore - simple, a url path will map to an action resource.

• Windows Only - Borderless will use Rossy's borderless that will not require Window Subclassing. Depending on feedbacks the current Window Subclassing may be re-added as an option.

Fixed issues

• Main entry point HTML page should be called index.html in project template #220
• How to return 404, 403 or any error code to renderer process ? #219
• Set Min windows size #218 - Windows Only.
• Support for new version .net core #216
• Allow to change serialization naming policy #209 - this should now be easier with .NET Extensions.