Create or load a repository (directory structure) containing sessions. The server internally maps the ID to its directories. If the server finds the repository, it will scan the corresponding directories, discover the sessions, process them and make them visible to the other clients. If the repository is not found, but bCreateIfNotExist is true, a new repository will be created. Repositories are persistent and visible to all server instances until dropped by the clients. Any server instance can mount a repository unless it is already mounted by another instance.