feat: SHA-256

[0xJepsen]

This issue serves as a discussion spot for implementation details and challenges of implementing SHA-256 in Binius.

The following are tasks necessary (but not necessarily sufficient) to be able to complete SHA-256.

• feat: rotate_right() function #3
• feat: sigma_0() function #4
• feat: sigma_1() function #5
• feat: small_sigma_0() function #6
• feat: small_sigma_1() function #7
• feat: ch() function #8
• feat: maj() function #9
• feat: input and padding #10

[Autoparallel]

Even more simply, I think we should work to create proofs for the operations used in SHA2. We can start with the 256 bit version as it's going to force us to figure out how to set up constraints and use the tower fields (as needed).

Let me make some issues.