* Create a P4Runtime service to be used by SONiC.
* Create a P4 Program describing a SONiC switch.
* Support pushing switch configurations.
* Support ACL table definitions.
* Support insert/delete/modify in APPL_DB.
* Support for L3 forwarding, WCMP, and ACL tables.
* Support for response path through APPL_STATE_DB.
* Support arbitration for multiple controllers and roles.
* Support PacketIO.
* Add Github Actions CI

Co-authored-by: Atman Mehta <atmanm@google.com>
Co-authored-by: Brian O'Connor <bocon@opennetworking.org>
Co-authored-by: Jonathan Dilorenzo <dilo@google.com>
Co-authored-by: Konstantin Weitz <konne@google.com>
Co-authored-by: Richard Yu <richardyu@google.com>
Co-authored-by: Robert Halstead <rhalstea@google.com>
Co-authored-by: Srikishen Pondicherry Shanmugam <kishanps@google.com>
Co-authored-by: Stefan Heule <heule@google.com>
Co-authored-by: Steffen Smolka <smolkaj@google.com>
Co-authored-by: Tianyu Xia <tyxia@google.com>