EditPage: Restore the old 'id' attributes in OOUI mode

EditPage: Restore the old 'id' attributes in OOUI mode

For compatibility with old scripts and extensions, we want the legacy
'id' on the `<input>` elements. There is really no good justification
for breaking all of them when we can easily support it.

The actual `<input>` elements have their ids back: 'wpSummary',
'wpSave', 'wpPreview', 'wpDiff', 'wpMinoredit', 'wpWatchthis'.

The widgets (wrapped `<div>`s) now use ids with 'Widget' appended.

Bug: T165854
Change-Id: I4d23f57fd0cda4b8539ffb17a2a19ecd822e077a