[Feature] Add support for HVM start_info page

[wipawel]

Is your feature request related to a problem? Please describe. In order to support PVH boot protocol (See rust-vmm issue) add proper detection and handling for HVM start_info page (info). This is needed to enhance Xen support as well as enable rust-vmm and Firecracker support.

Describe the solution you'd like Detect and parse HVM start_info page. Add handling for memory map entries, cmdline entry and module entries.