Add OPOS6UL_NANO compute module

Hello, this is the symbol for the OPOS6UL_NANO compute module. This module must be mated with a M.2M connector. Since I did not find any M.2 connector, I've created this footprint: kicad-footprints!2635 (closed)

Datasheet: http://www.opossom.com/_downloads/opos6ul_nano/datasheet_opos6ul_nano.pdf

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