Add SafeCast for all possible uintX types

[k06a]

🧐 Motivation
These methods are required when optimizing and tightly packing storage variables. We often use uint40 or uint48 for time and uint216/uint208 for the rest slot value, uint112 or uint96 (presented) for storing token amounts etc

[Amxx]

Hello @k06a and thanks for the suggestion

The casting contract contains a lot of code repetition. Ideally, we would have generics (c++ templates) supported by solidity ... but we don't live in that world. So we wait for requests, and we add them one at a time, which we probably both agree is not the right way to do.

IMO, these contracts should be generated procedurally, just like I did in this repo a few years ago (https://github.com/Amxx/SolStruct). @frangio would you be open to that idea?

[frangio]

Yes as long as they are all tested. What would that look like? Do we write a script and then commit the resulting Solidity file to the repository?

If we add all of the 32 functions we may want to review the documentation approach. Having virtually the same docstring for all 32 functions just adds noise.

[frangio]

Just took a look at SolStruct. I wouldn't follow this approach, it's too custom. I think either we use solpp or we just write a simple JavaScript program to generate the code (without using templates).

[Amxx]

Yes, I would have gone for a JS generator. SolStruct was just an example of procedural generation.