Remove Regorus and platform check for policy enforcement

[mgunnala]

Description

Issue #3219

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Policy unit tests fail on aarch64 environment, because the policy engine checks for supported architecture before invoking Regorus binary (Regorus is not yet supported on aarch64).

We will be removing the dependency on Regorus, so policy should now be supported on all distros and architectures. This PR does the following:

• remove the check for supported distro and architecture when enabling policy enforcement
• remove all calls to Regorus and any supporting code/tests. We only keep the few functions that will be utilized in the Python-based policy implementation (next PR).

This change should not affect functionality, because this feature was disabled by default, except in policy unit tests.

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• New Unit tests were added for the changes made

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