Add support for IP and L-Band SPARTN RTK correction sources

[semuadmin]

PyGPSClient Pull Request Template

Description

Add both IP and L-Band SPARTN RTK correction support to PyGPSClient.

Introduces a new SPARTN configuration dialog allowing users to configure IP (MQTT) and L-Band (D9*) correction data sources, and upload the necessary decryption keys to a SPARTN-compatible GNSS receiver (e.g. ZED-F9P).

Implements a new SPARTNReader class to parse individual SPARTN messages from a binary SPARTN data stream, and a skeleton SPARTNMessage to partially decode messages.

See README for further details.

Fixes # (issue)

Testing

Please test all changes, however trivial, against the supplied unittest suite tests/test_*.py e.g. by executing the tests/testsuite.py module or using your IDE's native Python unittest integration facilities. Please describe any test cases you have amended or added to this suite to maintain >= 99% code coverage.

• [x] New SPARTN parsing and static method tests

Checklist:

• [x] My code follows the style guidelines of this project (see CONTRIBUTING.MD).
• [x] I have performed a self-review of my own code.
• [x] I have commented my code, particularly in hard-to-understand areas.
• [x] I have made corresponding changes to the documentation.
• [x] (if appropriate) I have added test cases to the tests/test_*.py unittest suite to maintain >= 99% code coverage.
• [x] I have tested my code against the full tests/test_*.py unittest suite.
• [x] My changes generate no new warnings.
• [x] Any dependent changes have been merged and published in downstream modules.
• [x] I understand and acknowledge that the code will be published under a BSD 3-Clause license.