Fixes: U4-5190 Overwrite Media File in 6.2.1 - process cannot access along with a bunch of other undisposed disposables :/
Merge commit '874f464a2b51000920e2323f93bea116546e9b88' into 7.1.5

Conflicts:
	src/Umbraco.Core/IO/FileSystemExtensions.cs
	src/Umbraco.Core/IO/UmbracoMediaFile.cs
	src/Umbraco.Web/umbraco.presentation/umbraco/channels/UmbracoMetaWeblogAPI.cs