MB-12537: Rename all config files to *.conf

Some configuration files were named *.py. That might confuse tools that
expect all *.py to contain valud Python source code.

Change-Id: Ifa5d1c6f9311894c5f311d121fecb99cd9b2dcd0
Reviewed-on: http://review.couchbase.org/42785
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Ketaki Gangal <ketakigangal@gmail.com>