Added HALO Electronics ULTRA transformers family

Hello, I added the HALO Electronics package for their ULTRA discrete transformers.

Depends on !752 (merged)

Datasheet: https://www.haloelectronics.com/pdf/discrete-ultra-100baset.pdf

• Footprint MR: kicad-footprints!2754 (merged)
• Symbol MR: kicad-symbols!3396 (merged)