ChangesList: Expose basic properties of lines as data attributes

ChangesList: Expose basic properties of lines as data attributes

We have several types of change lists (old RC/watchlist/related
changes, enhanced RC/watchlist, history) with slightly different
HTML, each with their own idiosyncracies. JavaScript code trying
to identify lines by log ID / revision ID has to jump through all
kinds of hoops to work with that.

To simplify the lives of frontend / gadget maintainers and provide
something approaching an API for these pages, we now expose the basic
attributes of each change line (revision ID for edits, log type/action
and ID for log events) as data attributes.

The OldChangesListRecentChangesLine, EnhancedChangesListModifyLineData,
EnhancedChangesListModifyBlockLineData, PageHistoryLine,
ContributionsLineEnding and DeletedContributionsLineEnding hooks
are updated accordingly. New hooks (LogEventsListLineEnding and
NewPagesLineEnding) are added for the change list pages which did
not yet have them.

Change-Id: I6dd006d0b1b0fd35c0020f0f9eea9113eca30b35