docs/fingerprint: Add factory requirements for fingerprint
BRANCH=none
TEST=view in gitiles
* [Fingerprint MCU (FPMCU)](./fingerprint/fingerprint.md)
* [FPMCU Development for Partners](./fingerprint/fingerprint-dev-for-partners.md)
* [Fingerprint Authentication Design Doc](./fingerprint/fingerprint-authentication-design-doc.md)
+* [Fingerprint Factory Requirements](./fingerprint/fingerprint-factory-requirements.md)
## Updaters
