add API endpoints for getting & adding 3pids
add API endpoints for getting & adding 3pids

krombel/matrix-js-sdk,williamboman/matrix-js-sdk,krombel/matrix-js-sdk,krombel/matrix-js-sdk,matrix-org/matrix-js-sdk,williamboman/matrix-js-sdk,matrix-org/matrix-js-sdk,matrix-org/matrix-js-sdk,matrix-org/matrix-js-sdk,williamboman/matrix-js-sdk