Add a Doxyfile configuration for Doxygen.

Usage: run doxygen from doc directory to generate the LRC documentation.
The src/ directory is the source for inputs, scanned recursively.
A doc/html/ directory is then filler with all HTML files.
Browse index.html to read the LRC documentation.

Change-Id: Ieb4b5db6f690f47fab2e40358a142fe973412e9c
Reviewed-by: Nicolas Jäger <nicolas.jager@savoirfairelinux.com>

Nicolas Jager authored 7 years ago and Guillaume Roguez committed 7 years ago

add stubs for :
 - Database class.
 - ConversationModel class and Conversation namespace.
 - NewCallModel class and NewCall namespace.
 - ContactModel class and Contact namespace.
 - Message namespace.
 - NewAccountModel.
 - CallbacksHandler, will be used to bind the callbacks from the daemon
   and will emit signals for lrc and client.
 - Lrc class, this class is the root class of all models. Instating this
   class will build interfaces between the daemon, client and the
   database.
 - all these class are nested in the lrc namespace.
 - all publicly exposed API have been put into lrc::api namespace
 - add diagrams in doc folder

Change-Id: Ia06f874dd1baebb086edd570e52d8d61d73b905b
Reviewed-by: Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>
Signed-off-by: Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>