[Infrastructure] add common Postgres DB env vars to UDRG service

Add the following env vars to UDRG service compose file:

KPILIB_DB_HOSTNAME=postgres.local
KPILIB_DB_PORT=5432
KPILIB_DB_NAME=kpilibrary
KPILIB_DB_USER=
KPILIB_DB_PASSWORD=

/cc @imurua , @jabefa