Pull Request for Issue967: some UI changes

Altered:
UI changes for SXRMB Acquaman:
   - SXRMBPersistentView: add groupbox for Motors and Scalers
  - add more spaces for EXAFS Scan configuration view
  - 2D Scan configuration view: enlarge the width for "Beamling setting" so that it doesn't need to resize dynamically.

https://github.com/acquaman/acquaman/issues/967

@davidChevrier @dretrex