New builder setting to fix data source URI in manifest.json

Is your feature request related to a problem? Please describe.

Data source URI in manifest.json should not start with a slash in order to UI5 application work properly in a FLP.

Describe the solution you'd like

It would be nice to have a builder task or setting that checks manifest.json and strips off leading slash from a data source URI during a building of an application to ensure that URI is correct automatically.

Describe alternatives you've considered

There is a such feature in @sap/grunt-sapui5-bestpractice-build module that is not supported any more and should be replaced with @ui5/builder.

Additional context

Example of a data source section of manifest.json

  "dataSources": {
    "Document-RestSource": {
      "uri": "fnd/document-ms/",
      "type": "JSON"
    }
  }

Start by locating the @ui5/builder build-task or setting entry point that processes manifest.json. Use the dataSources example in this issue to determine how a leading slash should be handled, then identify or add the relevant build coverage and verify that the generated manifest contains the corrected URI.