Occlum SGX lib

Implementation for generate and verify SGX Quote

Usage:

``` use occlum_sgx::{SGXQuote, SGXQuoteBuilder};

fn main() -> Result<(), Box> { let buf = SGXQuoteBuilder::generatebytes("test data")?; let quote = SGXQuote::tryfrom(&buf)?;

println!("{:#?}", quote);

if quote.verify()? {
    println!("Quote is valid");
} else {
    println!("Quote is invalid");
}

Ok(())

} ```