Update PostgreSQL to version 18 (#10194)

Also, disable password-based authentication using the MD5 hash
algorithm, since that functionality has been officially deprecated:

https://www.postgresql.org/docs/18/auth-password.html

Signed-off-by: Anton Kirilov <[email protected]>

toolset/databases/postgres/postgres.dockerfile

@@ -1,9 +1,7 @@
-FROM postgres:17-bookworm
+FROM postgres:18-trixie
 
 ENV PGDATA=/ssd/postgresql \
     POSTGRES_DB=hello_world \
-    POSTGRES_HOST_AUTH_METHOD=md5 \
-    POSTGRES_INITDB_ARGS=--auth-host=md5 \
     POSTGRES_PASSWORD=benchmarkdbpass \
     POSTGRES_USER=benchmarkdbuser