Add Ag9900LP PoE DC/DC Footprint (repush of !2791)

Repush of !2791 (closed)

DS: https://silvertel.com/images/datasheets/Ag9900M-datasheet-ultra-miniature-isolated-Power-over-Ethernet-POE-module.pdf#page=16

Quite a few fixups:

• Add pin 1 marker
• Change drill to 1.12
• Redraw keepout as zone and match the DS dims
• Shrink pad sizes to stay out of keepout
• Change body to datasheet dims
• Correct pin spacing
• Change courtyard to datasheet values
• Expand description/tags
• 3D model path