Insert Link popup needs to be cleaned up

For a popup that carries out 5 different operations there are only 2 xwork actions (PagePicker and ViewAttachment), and 2 implementations (one for draft, one for page). This is far from ideal, and this configuration has been causing avoidable bugs (CONF-13388 and CONF-13252).

The main problems are:

1. PagePickerAction executes 5 operations (getHistoryPages, getSearchResults, getRecentlyUpdatedPages, getReferringPages and execute)
2. the attachment tab works in a completely different way to the rest of the tabs
3. wysiwyg-insertlink-popup.vm is littered with if statements that are very flaky. For example, the attachment tab and search tab both needs the spacekey parameter but for completely different operations.

Possible Solution

DraftManager should work more like PageManager so that confluence doesn't need to create 2 different implementations for retrieving what is essentially the same information. This would mean we can consolidate all our actions that we have split up to accomodate drafts (ViewPageAttachmentAction and ViewDraftAttachmentAction, ViewPagePickerAction and ViewPagePickerInDraftAction).
PagePickerAction should also be split up into 5 different actions so that it lines up more with the attachment tab.

Note: This is an issue that arose while fixing CONF-13388. PagePickerInDraftAction did not exist before CONF-13388 was resolved and was added as a quick fix but is not intended as a long term option.