Audit fixes

[SCMusson]

Starting on audit recommendations. The following are implemented

• lru_cache on uplc_unflat
• Evaluation of scripts can't use more resources than defined in protocol
• For submit_tx calls, check requested ExUnits are valid before execution.
• Maximum transaction size limits.

For allowing sessions to be shared between server workers the only real in-memory solution I can find seems to be using Redis.
This requires a Redis server to be set up in the background and currently I am just pickling entire Sessions for every API call.
Redis could also provide solutions for rate limiting and session cleanup which I will look into if we decide to move forward with Redis.

TODO assuming we move forward with Redis:

• Rate limiting
• Session cleanup
• Some Caching solution for sessions rather than retrieving and unpickling every API call.
• Refactor object serialisation by replacing full-object pickling with a more granular strategy, enabling selective updates and reducing unnecessary overhead.

The only other solutions I can think of for sharing sessions among workers is some kind of database. Redis, being in-memory, should be faster.

[coveralls]

Pull Request Test Coverage Report for Build 14646549674

Details

• 38 of 111 (34.23%) changed or added relevant lines in 3 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-2.9%) to 82.508%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
plutus_bench/mock.py	18	36	50.0%
plutus_bench/mockfrost/server.py	18	73	24.66%

Files with Coverage Reduction	New Missed Lines	%
plutus_bench/mockfrost/server.py	1	46.77%

Totals
Change from base Build 13635867589:	-2.9%
Covered Lines:	1599
Relevant Lines:	1938

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💛 - Coveralls