Audit the PolkaVM interpreter

[athei]

The interpreter will be deployed to the Polkadot runtime. It has to be audited. Audit to be done internally.

[Gioyik]

The audit was completed by April 30th. Shared the findings with @athei and @koute.

[Subway2023]

May I ask where I can find the audit results? I want to study what vulnerabilities exist in RISC-V virtual machines.