Add sample for retrieving signing information at runtime

[vtikoo]

Usecase:

User application wants to verify mrsigner, mrenclave information at runtime.

High level solution:

Mystikos exposes OE functions to fetch and parse raw SGX report via syscalls.

SYS_myst_oe_get_report_v2 -> returns a raw int8_t* report

Pass raw report to SYS_myst_oe_parse_report -> returns oe_report_t*
In the output of oe_parse_report (the third paramater), it will have type oe_report_t, one can access its enclave_report member
and then cast with sgx_report_body_t: openenclave/include/openenclave/bits/sgx/sgxtypes.h at 70bde076bd15bf786758a458c07dba33bb0e6938 · openenclave/openenclave · GitHub

From there you can access mrsigner and mrenclave
oe_report_t is defined here: openenclave/include/openenclave/bits/report.h at 70bde076bd15bf786758a458c07dba33bb0e6938 · openenclave/openenclave · GitHub

Exit criteria:

Samples in dotnet and C.