Add sharing of groups between databases

* 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

src/core/Database.h

@@ -23,6 +23,7 @@
 #include <QHash>
 #include <QObject>
 
+#include "config-keepassx.h"
 #include "crypto/kdf/Kdf.h"
 #include "keys/CompositeKey.h"
 
@@ -88,7 +89,7 @@ public:
     const Metadata* metadata() const;
     QString filePath() const;
     void setFilePath(const QString& filePath);
-    Entry* resolveEntry(const QUuid& uuid);
+    Entry* resolveEntry(const QUuid& uuid) const;
     Entry* resolveEntry(const QString& text, EntryReferenceType referenceType);
     Group* resolveGroup(const QUuid& uuid);
     QList<DeletedObject> deletedObjects();
@@ -149,7 +150,7 @@ private slots:
     void startModifiedTimer();
 
 private:
-    Entry* findEntryRecursive(const QUuid& uuid, Group* group);
+    Entry* findEntryRecursive(const QUuid& uuid, Group* group) const;
     Entry* findEntryRecursive(const QString& text, EntryReferenceType referenceType, Group* group);
     Group* findGroupRecursive(const QUuid& uuid, Group* group);