[breadcrumbs] Small breadcrumb components refactoring
* use `open_breadcrumbs` and `close_breadcrumbs` methods where applicable in
the BreadCrumbEntityVComponent hierarchy
* include the first separator related code in `open_breadcrumbs` to avoid code
duplication
Closes #3223911.
[views/dot] use an inlined svg for schema and workflow graphs
These are currently served as "temporary" pngs which are actually consummed immediately.
Which means they cannot be requested twice and any further attempt will yield an error
in the logs and some end-user surprise.
There is no known acceptable workaround for IE-8 (and previous versions). SVGWEB could
be workable but it's not trivial to integrate it properly.
Closes #3400448.