Consider using a URI Template for test_config

[MartinFlores751]

URI Template RFC for those curious: https://www.rfc-editor.org/info/rfc6570

The following three lines can be merged into one:

irods_client_http_api/test/config.py

Lines 7 to 9 in 3824a09

	'host': 'localhost',
	'port': 9000,
	'url_base': '/irods-http-api/<version>',

The option would end up looking like the following:

'test_uri': 'http://localhost:9000/irods-http-api/{version}'

And can be validated using 'format': 'uri-template' in the JSON schema.

We can then substitute the version in code, if we desire for more automated tests as well.