[O] Some internal libraries still depend on org-bbdb and org-bibtex

[Jonas Bernoulli]

Hello

In 499c0a50cc4b11e37b91374af23cb27ab8fc20d2 some libraries were
renamed, but some other libraries continue to depend on the old
features:

- lisp/ox-icalendar.el still depends on org-bbdb
- contrib/lisp/org-bibtex-extras.el still depends on org-bibtex

Overall this change did not cause too much work for third-parties
I think.  I have opened issues for all the packages known to the
Emacsmirror that still depend on the old features:

- https://github.com/ruediger/bibeltex/issues/2
- https://github.com/andras-simonyi/citeproc-el/issues/7
- https://github.com/unhammer/gnus-recent/issues/13
- https://github.com/seanohalpin/org-link-minor-mode/issues/7
- https://github.com/aki2o/org-linkany/issues/4
- https://github.com/claviclaws/org-mac-protocol/issues/8
- https://github.com/jkitchin/org-ref/issues/649

Cheers,
Jonas