Add test printed circuit board project

[apcountryman]

Add test Printed Circuit Board (PCB) project. The proposed design was outlined in #42.

Key PCB features (as outlined in #42):

• The PCB will be a breakout board for the Maxim Integrated MAX6683 (datasheet) temperature sensor and system monitor.
• All MAX6683 signals will be brought out to the breakout board's pin headers.
• The signals that are brought out to the breakout board's pin headers will use the same arrangement that is found on the MAX6683.
• Solder jumpers will be used to configure the MAX6683's I2C address (see Sparkfun's Texas Instruments TMP117 breakout board schematic for reference).
• I2C pull-up resistors will be provided, but the user will be able to cut the normally connected solder jumpers to disable them (see Sparkfun's Texas Instruments TMP117 breakout board schematic for reference).

This test project will be used to test this repository's Continuous Integration (CI) jobs. The Pull Request (PR) that implements this test project should not implement fixes for any CI job bugs that are discovered. CI job bugs should be reported in their own issues and fixed by dedicated PRs.

The following CI job features should be verified during development of this feature. CI job failures should be deliberately triggered when possible during development to ensure the CI jobs are working properly.

• (optional) KiCad Library Convention (KLC) compliance violations are detected
  • This is optional because the KLC compliance CI job was copied from https://github.com/apcountryman/prototype-kicad-library-ci where it was already tested. Recommend just using the official part libraries if they support all parts required by the breakout board.
• Electrical Rules Check (ERC) error detection
• Design Rules Check (DRC) error detection
• Schematic PDF generation
• Tradition Bill of Materials (BOM) generation
• Interactive BOM generation
• Production files generation
• PCB renders generation