Add keyboard shortcuts to move focus by loop

Move to next loop shortcut and move to previous loop shortcut.

If focus is not on the program, the shortcuts would take you to the first and last loops in the program.

If the action panel is open for a program block, the shortcuts would close the panel and take you to the appropriate loop.

Original Jira issue: https://fluidproject.atlassian.net/browse/C2LC-622