Update the help Makefile.am

…so that the build isn't broken.
Remove index.docbook.
Link to help index
Add help stubs

initial commit of basic seahorse task stubs. linking not yet established.
docs: modify index page to include seahorse icon.

Move to media
docs: added page about certs. initial draft of ssh-key description.
docs: added draft to explain public vs private keys.
added draft page on how to create a pgp key.
docs: updated index page. cleaned up key creation pages. added simple page to summarize adding keys.
docs: updated index page. cleaned up key creation pages. added simple page to summarize adding keys.
docs: added group and groups information to learning sections. reworked what-diff-priv-public page
docs: refactored the landing page, moving general info about keys to a separate sub-page.
docs: fixed validation error on learn-about-keys.page
help: Comment on some of the 'learning' pages

Hopefully this commit will be squashed when me merge this branch.
But we can worry about that later.
Added a list of basic terms in introduction.page

Explanation of some technical terms involved.
help: Update introduction.page
help: Added draft for encryption-rsa.page
help: add <include> tag on encryption-rsa.page
help: Update key-servers-what-are-they.page
help: New keys pages: sync, retrieve