Use WorkspaceFolder instead of URIs in IWorkspaceContextService

* drop workspace ID from workspace file

* make folders types an object instead of just string

* fix compile

* polish relauncher for id change

* migrate old workspace format to new on startup

* more migration from previous workspace id

* more migration code

* change folder format to be a path

* support for relative paths in workspace file

* fix of ctor call

* put root validation and filtering into workspace

* ensure we always have file resources

* fix tests

* add tests for workspace

* 💄

* linting