[UBCL] Ubcl endpoints fallback depending on UBCL library support

[EmmanuelBRELLE]

Most recent versions of UBCL may return UBCL_ERR_NOT_AVAILABLE on the endpoint initialisation (based on both the UBCL library configuration and the requested endpoint type). This PR patches pml/ubcl endpoints creation to handle these error codes and to fallback on an higher (self-> shared memory -> network) endpoint type. This make pml/ubcl endpoints to be more resilient.