Add MKR symbol and footprint

[forrestbao]

No description provided.

[Alarm-Siren]

Hi there. Thank you for submitting this. I shall try to find some time to review it.

[Alarm-Siren]

Whilst this is a good start, it does not meet the standards of what I would be willing to merge into mainline.

The main things I'd be looking for improvement:

• There are multiple MKR boards, some with slightly different layouts (e.g. MKR NB 1500 vs MKR Zero), and whilst its not necessary to add all MKR boards at once, the library should make explicit which exact boards each footprint or symbol are compatible with.
• The symbol neither follows the Kicad Library Conventions (see Update the library to reflect the new Kicad Library Convention #26), nor follows the style I use in the rest of library (e.g. pins grouped by function). For the sake of consistency I would like to see these followed.
• The footprint lacks the mechanical screw holes present on the MKR series boards, nor does it have rounded corners to match; I cannot add these as I do not have accurate mechanical drawings for any MKR series board, nor do I own one.
• Neither the footprint nor symbol have their metadata properties setup (e.g. description, tags, documentation links).

Most of these I can rectify myself if necessary, but I would need the accurate mechanical drawings of the MKR boards we're aiming to add, or access to a MKR.

Reference #27 .

[Alarm-Siren]

Changes were never actioned, nor mechanical drawings provided. Closing this pull request.