Open a sword v3 compliant deposit implementation

The specs [1] and compulsed differences between the protocol versions [2] are defined in the sword site.

As noted, the sword v2 implementation stays.

• [1] https://swordapp.github.io/swordv3/swordv3.html

• [2] https://swordapp.github.io/swordv3/differences-to-swordv2.html

---

Migrated from T2794 (view on Phabricator)