vmm: Implement the VM HTTP endpoint handlers

Implement the vm.create, vm.boot, vm.shutdown and vm.reboot HTTP endpoint
handlers.

Fixes: #244

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

vmm/src/api/mod.rs

@@ -34,6 +34,7 @@ extern crate vmm_sys_util;
 pub use self::http::start_http_thread;
 
 pub mod http;
+pub mod http_endpoint;
 
 use crate::config::VmConfig;
 use crate::vm::Error as VmError;