Create tapicero.md

Copy tapiceros readme into leap_doc.
Add tapicero to menu
Add database setup section to overview

Explaining setup of 'normal' and per-user databases. link to tapicero, point out where the design docs come from and where they go.
Emphazise usage within leap platform for tapicero

Sorting the sections so the usage scenarios for the platform come first.
added secure email report.
added services <> node type table.
expanded the key validation problem to be a general 'key management problem'
added brief mention of ZRTP
pull secure-email from upstream
refreshed secure-email from upstream
Merge pull request #7 from azul/tapicero

Initial Tapicero documentation
move webapp documentation into the docs
remove bash hints from code blocks
remove github specific code block style
Capitalize Design Docs properly and make them a h2
Updated docs to reflect issues of bug #5601

The docs reflect the problem when adding new couchdb nodes after one o
more have been deployed.