Structure developer documentation

- rename target "doc-dev"
- group into modules
- move to doc/dev

src/cmd/simplesslerrorhandler.cpp

@@ -15,6 +15,8 @@
 #include "account.h"
 #include "simplesslerrorhandler.h"
 
+namespace OCC {
+
 bool SimpleSslErrorHandler::handleErrors(QList<QSslError> errors, const QSslConfiguration &conf, QList<QSslCertificate> *certs, OCC::AccountPtr account)
 {
     (void) account;
@@ -30,3 +32,5 @@ bool SimpleSslErrorHandler::handleErrors(QList<QSslError> errors, const QSslConf
     }
     return true;
 }
+
+}