Caller Lists Environment Variables

The following environment variables are relevant for the Caller Lists microservice:

`DB_URL`	This is the Database connection URL. Database name (`db_name`) for caller list should be the same, as of Supervisor Tools (db_name) For example: jdbc:jtds:sqlserver://<MACHINE-IP or FQDN>:PORT/db_name jdbc:jtds:sqlserver://<MACHINE-IP or FQDN>:PORT/db_name;instanceName=SomeInstance
`DB_USER`	database user
`DB_DRIVER`	JDBC driver e.g., net.sourceforge.jtds.jdbc.Driver
`DB_DIALECT`	Database dialect e.g., org.hibernate.dialect.SQLServer2008Dialect
`DB_PASS`	database password