Support multiple contribution areas

[clairernovotny]

The MVP site now allows adding contributions and tagging them with multiple contribution areas. Would be great if the app could support that too.

[LanceMcCarthy]

Almost done adding this! I'll try to get it out by the end of the weekend.

[LanceMcCarthy]

Completed first successful test for this in the https://github.com/LanceMcCarthy/MvpApi/tree/multiple-categories branch.

The feature is implemented on the Contribution Details page (where you can edit an existing contribution).

Here's a video of it in action https://twitter.com/lancewmccarthy/status/1043250453948129281

[LanceMcCarthy]

This is ready to use in the latest commit https://github.com/LanceMcCarthy/MvpApi/commit/88731d9edbb9635e6c441bc90a7c5fb4e37b44a7 to the Multiple Categories Branch.

AdditionalAreas SelectedItems Binding Issue

There is one bug left before PR and publishing this update When examining an existing contribution, the number of Additional Technology Areas still shows and they're saved properly. The problem is with the Flyout ListView, the Additional Areas are not pre-selected even though they are valid. To track this issue, see https://github.com/LanceMcCarthy/MvpApi/issues/49

[LanceMcCarthy]

The bug appears to be unavoidable, I have redesigned the way you edit Additional Areas and will submit the update in this state. If the underlying problem with multiple selection is determined, I'll update again.

[LanceMcCarthy]

Released in v1.6:

• It will have an initial 25% staged roll out to make sure there are no major problems.
• If you manually check for updates, or use direct URL, you will get 1.6

[LanceMcCarthy]

https://www.microsoft.com/store/productId/9NRXNX3WLH77