Add FIPS switch

[dkirov-dd]

What does this PR do?

This PR adds the following functionality to the AgentCheck base class:

• When the GOFIPS environment variable is set to 1, the OPENSSL_CONF and OPENSSL_MODULES environment variables are modified in order to point all OpenSSL binaries to the desired configuration and modules.
• This will enable FIPS by default for all calls made with the OpenSSL binaries, as documented here.

Motivation

We want to ensure that all integrations can function in a FIPS compliant mode if it is necessary.

Implementation decisions

The GOFIPS environment variable was set as the FIPS toggle indicator by the ASC team.
Environment variables were preferred to C function calls for two main reasons for simplicity and reliability. The limitation of environment variables is that they have no effect on already loaded OpenSSL configurations. However, since there is no requirement for a toggle to FIPS mode during runtime, this is not an issue as we can load the correct configuration on startup.
The reason why the implementation should live in the base check is to be as close to the start of the Python process as possible, to prevent any OpenSSL configuration loading before the env vars are set.

Testing

Two types of automated tests were attempted:

• E2E tests using the TLS check: we are checking if the TLS check can communicate with a custom server that restricts its accepted ciphers to a single one. When that cipher is not FIPS approved and we are running in FIPS mode, communication should fail. It should succeed in all other cases.
• (WIP - Will be added in follow-up PR) Integration tests: testing our enable_fips outside of the Agent container environment. These tests are verify that our FIPS switch has an effect on cryptographic libraries like ssl and cryptography. They are run in the test-fips workflow which is very much experimental.

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Add the qa/skip-qa label if the PR doesn't need to be tested during QA.
• If you need to backport this PR to another branch, you can add the backport/<branch-name> label to the PR and it will automatically open a backport PR once this one is merged