Correctly manage inspection status in offline mode

[iamkinetic]

• [x] Auto create building's copy when first downloading an inspection.
• [x] Auto create visit on first download.
• [x] We need to be able to enter in an inspection before it has been downloaded.
• [x] The "start visit" should also download the inspection (+ copy + auto create first visit).
• [x] The "start visit" should set the "start date" in offline data.
• [x] The "End visit" should set the end date" in offline data.
• [x] Correctly display the inspection as "ready to transfer" in the list.
• [x] Correctly display the inspection as "ready to transfer" in the inspection-general page.

Many user should be able to download an inspection, but only the first one will make it create the visit and the copy.