Added MPS MP4247 Buck/Boost converter

Links

Datasheet: https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/MP4247GQV/document_id/9935/
Footprint MR: kicad-footprints!3156

KLC issues:

• S4.2 and S4.4: VCC is not a power input / power pin. Its the output of the internal regulator. I've not put them on top as regulators usually don't have them on top

Screenshots