Windows: NSIS installers for AFS Redirector

Windows: NSIS installers for AFS Redirector

These changes provide basic support for installing
the AFS Redirector and the AFSRDFSProvider.dll.
However, since NSIS is not useful for 64-bit installations
the NSIS installers will be removed from the source tree
in the near future.

1.7.x series will not be distributed with NSIS installers.

Change-Id: Ifd9d06af4f047e27c23c87af79ba84085bc3614a
Reviewed-on: http://gerrit.openafs.org/5441
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>