Add new Allegro current sensor footprints

These are the footprints needed for the library update at https://github.com/KiCad/kicad-library/pull/1817.

Datasheet links:

• PSOF: http://www.allegromicro.com/~/media/Files/Datasheets/ACS780-Datasheet.ashx
• QFN: http://www.allegromicro.com/~/media/Files/Datasheets/ACS711-Datasheet.ashx
• QSOP: http://www.allegromicro.com/~/media/Files/Datasheets/ACS726-Datasheet.ashx
• SIP-4: http://www.allegromicro.com/~/media/Files/Datasheets/A1363-Datasheet.ashx
• SIP-3: http://www.allegromicro.com/~/media/Files/Datasheets/A1369-Datasheet.ashx

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