dblink: Replace WAIT_EVENT_EXTENSION with custom wait events
Two custom wait events are added here:
- "DblinkConnect", when waiting to establish a connection to a remote
server.
- "DblinkGetConnect", when waiting to establish a connection to a remote
server but it could not be found in the list of already-opened ones.
Author: Masahiro Ikeda
Discussion: https://postgr.es/m/
197bce267fa691a0ac62c86c4ab904c4@oss.nttdata.com