Add support for bus lock detection (`KVM_CAP_X86_BUS_LOCK_EXIT`).

[00xc]

Summary of the PR

Add support for bus lock detection. The feature can be enabled via KVM_CAP_X86_BUS_LOCK_EXIT, which enables a new exit (KVM_EXIT_X86_BUS_LOCK) and a new flag (KVM_RUN_X86_BUS_LOCK) in the kvm_run->flags field.

Add two tests as well to verify that enabling the feature works

Requirements

• [X] All commits in this PR are signed (with git commit -s), and the commit message has max 60 characters for the summary and max 75 characters for each description line.
• [X] All added/changed functionality has a corresponding unit/integration test.
• [X] All added/changed public-facing functionality has entries in the "Upcoming Release" section of CHANGELOG.md (if no such section exists, please create one).
• [X] Any newly added unsafe code is properly documented.

[JonathanWoollett-Light]

@00xc Can you please resolve the merge conflicts, after this LGTM.

[00xc]

Rebased on main and fixed conflicts.