* register a new IPackageManifestReader to allow to scan the /umbraco/backoffice path for umbraco packages
* add constant
* add logic to extract the importmap from umbraco package manifests
* add html helper to render an importmap
* replace static importmap with new dynamic importmap
* update tests and be more specific about scopes
* remove recursion from PackageManifestReader.cs
* add extra test to validate the importmap
* combine all string manipulation to produce an importmap into HtmlHelperBackOfficeExtensions.cs
* rename IStaticFileHostGenerator to something reflecting its actual usage, and also fix the file names
* use auto properties where applicable
* add getter for BackOfficeHash and use to simplify BackofficeAssetsPath
* ensure BackOffice is always spelled with capital O
* add a way to replace the cachebuster for assets imported through an importmap and ensure magic strings are encapsulated into business logic or constants
* Review changes
* convert primary constructors to explicit and add comments
* convert primary constructor to explicit
---------
Co-authored-by: kjac <kja@umbraco.dk>
d0145ed7e9