Umbrella: Improve Form Builder usability

[ebruchez]

Top issues:

• Advanced Form Builder keyboard shortcuts #4609
• FB: Ability to move rows, columns and maybe cells within a grid #127
• FB: Don't require opening so many dialogs #762
• Form consistency check functions #1491
• In dialogs, don't disable save/apply button #646
• Previous/next navigation in Settings dialog #2587
• FB: 12-column grid layout #2738
• Ability to move controls with drag and drop #1479
• Ability to move/reorder grids up/down within/across sections #1845
• Basic Form Builder keyboard shortcuts #233
• Combine Section/Grid Settings and Section Help dialogs #1161