Backports fix from 7 for GetDimensions call to ensure the file exists
Fixes: U4-5208 RenderActionInvoker needs to be able to run async so needs to inherit from AsyncControllerActionInvoker
Fixes an xss vulnerability
fixes a single vs first check with render route handler when there might be duplicate routes assigned to a controller, fixes short/int parse
Fixes: U4-5207 User Type with a space in the name breaks User Content
Merge remote-tracking branch 'origin/6.2.2' into 7.1.5

Conflicts:
	src/Umbraco.Core/IO/UmbracoMediaFile.cs