Add pgconf module to spec helper.
Add reference to pgconf in fixtures.yaml
Replace file_line resources by postgresql::pg_conf_entry
Update postgres module with commands for high availability

The following commands are added.
wal_level max_wal_senders wal_keep_segments archive_mode archive_command hot_standby
Manage postgresql.conf entries
Update name from pg_conf_entry to config_entry
Move puppet/pgconf module to postgresql module
Dont specify parameters we dont want to manage separately.
remove cycle
Adding unit tests, and fixing comment treatment

Added unit tests, and updated the logic to fix the problem when comments
part of the line were not getting set. Also ensured that includes were
quoted