General-purpose toolchain

[nkaskov]

Toolchain on this stage has to be able to provide circuits compilation of different types of logic not being limited to some predefined cases such as zk-Bridges or something. It might be not as efficient for some particular cases, but it has to be able to support them.

• Rework memory-related operations #208
• Support building stdlib as IR library #196
• Add recursive mode #287
• Fix comparison instructions handling #187
• Introduce private input support #205
• Add SHA2-512 hash intrinsic to Rust #291
• Add SHA2-256 intrinsic to Rust compiler #285
• Add curve types to Rust frontend #254
• Handle curve comparison properly in the assigner #240
• Implement enforced comparison via intrinsic #274
• Add new intrinsics for Placehloder verification circuit #300
• Adding lookup table support #340
• README is lacking instructions about building rslang from sources #359
• Remove not-public-input values from the public input column #339
• [Feature request]: Need an implementaion of abs() function #391
• Enable getelementptr_as_constant test #399