Remove upload form to Aggregate menu item

[yanokwa]

Aggregate is EOL. We should remove the Upload form to Aggregate and maybe throw up a pop-up when people attempt to use it.

[florianm]

Involved code

server/views/index.erb

• Menu File > Upload Form to Aggregate: change from "upload" modal to "deprecation warning" modal
• Modal .aggregateDialog: Change/replace with deprecation warning / pointer to central.

The following sections can be deleted or commented out to preserve working examples:

public/javascripts/data-ui.js

• Handler for "Export" button in aggregate modal connects to post '/aggregate/post' and handles the ajax request.

server/odkbuild_server.rb

• Upload method post '/aggregate/post': remove or comment out and keep as starting point for #227

public/stylesheets/styles.css

• Styles for modals can be useful for other modals

public/javascripts/modal.js

• Helper for aggregate modal "exporting" indicator

Implementation

Option 1: remove

The MVP is to simply disable the menu item without warning or replacement. However, this could feel abrupt to experienced Build users.

Option 2: replace with warning

Maybe the most gentle way forward could be to replace the "Upload Form to Aggregate" modal with an informative text that warns the user of Aggregate's deprecation, provides instructions to upload the form to Aggregate manually for the last remaining Aggregate operators, and suggests Central / Forum as way forward.

Option 3: keep and add warning

The least jarring change is to retain the upload to aggregate functionality and only add the deprecation warning to the modal.

Skeleton of deprecation warning:

ODK Aggregate has reached its end of life and is unsupported. We recommend to use ODK Central.
You can still export the form to XML and manually deploy it to Aggregate.

@yanokwa which option would you prefer? What's a good "ODK style" text for the deprecation warning?