Implement AJAX Summary Displays.

[bri-gaia]

Add option to render summary displays using AJAX.

[collectiveaccess]

This is PR with changes in 23 files. Can you provide something more than a one line description of what you're trying to accomplish here, and why it is necessary?

[bri-gaia]

Some of the data we are displaying in the summary tab is quite heavy, so we implemented AJAX loading so that the page would render immediately and we could show a loading graphic.

By individually loading in the data elements the smaller requests can be populated without being held up by the more intensive queries.

I have requested that my tech lead provide additional context to this PR if possible.

[kehh]

@collectiveaccess what @bri-gaia has put above is pretty much the gist of it. Essentially very complex templates can take some time to render especially if they are traversing many relationships / aggregating values from all descendants. This allows the page to render without being held up by slower templates.

[kehh]

There's a switch for this functionality in app.conf - that could be defaulted to off if you prefer?

[bri-gaia]

Additional info:

• The crux of the change of this is implemented in BaseEditorController.php refactoring Summary() into separate functions that can be called individually if configured to us AJAX while maintaining the current functionality if AJAX is not enabled.
• I have implemented renderGeneric() and updated the call to template_test_html.php as the relative path only worked for summary's under the themes/default/views/editor directory, causing issues with, for example, the list_editor.
• The changes to the 17 summary_html.php files should all be identical, and I have attempted to modify as little in those files as possible to make that visible.

Apologies for the massive PR.