Add progress spinner/bar while loading data in mUzimaCore module

The forms tab on mUzima Core modules shows a progress bar to indicate forms are being loaded, and the progress bar disappears once forms have loaded ready for display.

Other tabs, such as the Error data tab does not provide such a progress bar and is sometimes misleading users to indicate no data is available for display, but later displays the data once loading is completed.

There is a need to update the Core module UI to show progress spinner/bar for all other tabs, similar to the forms tab.