feat: introduce CosimM to store platform features in a cache

[bollu]

Closes #97 .

Description:

We implement a CosimM monad that tests platform features via platform_features.sh once. These are then used during instruction generation time. e.g. the presence/absence of SHA-512 instructions.

At least locally, I observe a modest decrease in wall clock time:

before

real 131.23
user 79.43
sys 67.27

after

real 126.06
user 75.35
sys 60.94

License:

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[bollu]

@shigoel fixed parens.

[bollu]

@shigoel merged to synchronize with latest upstream/master. I feel this can be merged, and we can improve CosimM iteratively to save more data.