agent: Show features enabled at build time

The agent now has a number of optional build-time features that can be
enabled.

Add details of these features to the following areas:

- Version output (`kata-agent --version`)
- Announce message (so that the details are always added to the journal
  at agent startup).
- The response message returned by the ttRPC `GetGuestDetails()` API.

Fixes: #9285.

Signed-off-by: James O. D. Hunt <james.o.hunt@intel.com>

src/runtime-rs/Cargo.lock

@@ -3690,6 +3690,7 @@ dependencies = [
  "hyperlocal",
  "kata-sys-util",
  "kata-types",
+ "nix 0.24.3",
  "tokio",
 ]
 

src/runtime-rs/crates/agent/src/kata/trans.rs

@@ -747,6 +747,7 @@ impl From<agent::AgentDetails> for AgentDetails {
             device_handlers: trans_vec(src.device_handlers),
             storage_handlers: trans_vec(src.storage_handlers),
             supports_seccomp: src.supports_seccomp,
+            extra_features: trans_vec(src.extra_features),
         }
     }
 }

src/runtime-rs/crates/agent/src/types.rs

@@ -527,6 +527,7 @@ pub struct AgentDetails {
     pub device_handlers: Vec<String>,
     pub storage_handlers: Vec<std::string::String>,
     pub supports_seccomp: bool,
+    pub extra_features: Vec<std::string::String>,
 }
 
 #[derive(PartialEq, Clone, Default)]