Draft: Feature/mongo db

MongoDB implementation of the long-term memory as part of the bachelor thesis of Robin Müller (utwee_mueller).

Tasks:

• implement a Mixin for the MongoDB version of the LTM
  • set-up and connection to database
  • writing into the database
  • reading from the database
  • adjusting keys
• test MongoDBMixin for different memory servers
  • VisionMemory
  • ObjectMemory
  • RobotStateMemory
  • GraspMemory
  • ...
• Implement an autonomous key selection algorithm

source/RobotAPI/libraries/armem/server/ltm/detail/mixins/util/mongodb.cpp

@@ -81,7 +81,7 @@ namespace armarx::armem::server::ltm::util::mongodb
 
     std::optional<mongocxx::database> 
     databaseExists(mongocxx::client& client, const std::string& databaseName) {
-    // MongoCXX Version > 3.4.0 required 
+    // MongoCXX Version > 3.5.0 required 
     /*
     auto names = client.list_database_names();
     if (auto it = std::find(names.begin(), names.end(), databaseName); it != names.end()) {
@@ -93,7 +93,7 @@ namespace armarx::armem::server::ltm::util::mongodb
     // Compatibility with older MongoCXX versions
     mongocxx::cursor dbs = client.list_databases();
     for (auto &view : dbs) {
-        if (view["name"].get_string().value == databaseName) {
+        if (view["name"].get_utf8().value == databaseName) {
             return client[databaseName];
         }
     }