This introduces another generic "button-like" class that can
be reused in multiple places in the new sidebar. The main
change in this patch is the "add more information" button
which is now an instance of this new class as well.
This patch also simplifies over-complicated setup code in
related widgets.
Bug: T274544
Change-Id: I0cfe7675d02fdd5c5dc8d9198bb3f4aec9abf397
The two new widgets are pretty trivial now, thanks to the base
class.
Note there is still no code to delete the widgets. That's also
why you will always see a placeholder widget at the top. This
will be fixed with the next patches.
This patch also renames most of the "…TemplateOutline…" classes
to "…TransclusionOutline…" The reason is that these widgets are
not for a single template, but part of the container widget for
a more complex transclusion (i.e. a sequence of multiple
templates and wikitext snippets).
Bug: T274544
Change-Id: If4219b0b8ad4d1969ab1ec5ec4db0728811bab35
