Fixes: #2306

Summary:

• Historically JSB objects are cached per process, for shared render processes this can be problematic
  This optionally allows for a new Per Browser cache.

Use the following command line arg to opt into this behaviour.

--jsb-cache-perbrowser

// CefSettings
settings.CefCommandLineArgs.Add("jsb-cache-perbrowser");

Changes:

• Add cache abstraction to allow for legacy and new per browser configuration
• Add new CefSharp specific command line arg to optionally enable new code path
• Settings haven't been moved to per Browser as that requires additional code changes to pass in extraInfo to the Popups

How Has This Been Tested?
TODO: Add tests

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Updated documentation

Checklist:

• Tested the code(if applicable)
• Commented my code
• Changed the documentation(if applicable)
• New files have a license disclaimer
• The formatting is consistent with the project (project supports .editorconfig)