Adding debug info to the CLI and the general option
of the main Qt app. Also took time to:
* use `EXIT_SUCCESS`/`EXIT_FAILURE` constants
for main.cpp (this is what is used in `src/cli`);
* fixed `m_initalized` typo;
* added info on debugging mode being disabled
or not;
* regrouped Qt related stuff in the debug output.
* Add source folder keeshare for sharing with corresponding define WITH_XC_KEESHARE
* Move common crypto parts to src/crypto/ssh
* Extended OpenSSHKey
* Move filewatching to own file (currently in two related classes DelayedFileWatcher and BulkFileWatcher)
* Small improvements for style and code in several classes
* Sharing is secured using RSA-Keys which are generated on demand
* Publisher signs the container using their private key
* Client can verify the signed container and choose to decline an import,
import only once or trust the publisher and automatically import all
data of this source henceforth
* Integration of settings into Group-Settings, Database-Settings and Application-Settings
* Introduced dependency QuaZip as dependency to allow combined export of
key container and the (custom format) certificate
