Convert license to SPDX format adding many missing licenses
The majority of code is GPL-2.0 or LGPL-2.1, but a few random extra
licenses are found in certain files which appear to make it into the
binary RPMs:
W3C: gauth/serviceImpl/schemas/xmldsig-core-schema.xsd
ICU: lib/misc/codeset.c
ISC: lib/misc/base64.c
MIT: lib/misc/codesetUTF8.c
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>