Support for ISO 19115 Part 3 XML

[vjf]

Overview - Support for ISO 19115 Part 3 XML

This PR contains a new profile for pycsw, called 'iso19115p3'.

• The profile is in 'pycsw\pycsw\plugins\profiles\iso19115p3', this includes a new outputschema
• There is a new file 'mdb/py' in 'pycsw/pycsw/core' that contains classes used to parse the XML.
• There is a unit test for 'mdb.py' in 'pycsw\tests\unittests\test_mdb.py'
• There are function tests in 'pycsw\tests\functionaltests\suites\mdb'

Related Issue / Discussion

Additional Information

Contributions and Licensing

(as per https://github.com/geopython/pycsw/blob/master/CONTRIBUTING.rst#contributions-and-licensing)

• [X] I'd like to contribute ISO 19115 Part 3 support for pycsw. I confirm that my contributions to pycsw will be compatible with the pycsw license guidelines at the time of contribution.
• [X] I have already previously agreed to the pycsw Contributions and Licensing Guidelines