Docs: Adding verify measure, host-data, report-data to docs

Adding instructions and changes to documentation
on how to use the optional features measure, host-data,
and report-data features added to the verify attestation
command.

Signed-off-by: Arvind Kumar <arvinkum@amd.com>

Author: arvindskumar99

.Cargo.toml.un~

@@ -306,7 +306,7 @@ snpguest verify <SUBCOMMAND>
 
     **Usage**
     ```bash
-    snpguest verify attestation $CERTS_DIR $ATT_REPORT_PATH [-t, --tcb] [-s, --signature]
+    snpguest verify attestation $CERTS_DIR $ATT_REPORT_PATH [-t, --tcb] [-s, --signature] [-m, --measurement] [-d, --host-data] [-r, --report-data]
     ```
     **Arguments**
 
@@ -318,6 +318,9 @@ snpguest verify <SUBCOMMAND>
 
     - `-t, --tcb`: Verify the Reported TCB section of the report only.
     - `-s, --signature`: Verify the signature of the report only.
+    - `-m, --measurement`: Verify the measurement from the attestation report.
+    - `-d, --host-data`: Verify the host-data from the attestation report.
+    - `-r, --report-data`: Verify the report-data from the attestation report. 
 
     **Example**
     ```bash
@@ -327,6 +330,12 @@ snpguest verify <SUBCOMMAND>
     snpguest verify attestation ./certs attestation-report.bin --tcb
     # Verify Attestation Signature only
     snpguest verify attestation ./certs attestation-report.bin --signature
+    # Verify Attestation Measurement only
+    snpguest verify attestation --measurement 0xf28aac58964258d8ae0b2e88a706fc7afd0bb524f6a291ac3eedeccb73f89d7cfcf2e4fb6045e7d5201e41d1726afa02 /home/amd/certs /home/amd/report.bin
+    # Verify Attestation host-data only
+    snpguest verify attestation --host-data 0x7e4a3f9c1b82a056d39f0d44e5c8a7b1f02394de6b58ac0d7e3c11af0042bd59 /home/amd/certs /home/amd/report.bin
+    # Verify Attestation report-data only
+    snpguest verify attestation --report-data 0x5482c1ffe29145d47cf678f7681e3b64a89909d6cf8ec0104cfacb0b0418f005f564ad14f5c1381c99b74903a780ea340e887c9b445e9c760bf0b74115b26d45 /home/amd/certs /home/amd/report.bin 
     ```
 
 ### Global Options

Cargo.lock

@@ -120,12 +120,25 @@ COMMANDS
     An error will be raised if the attestation verification fails at any point.
     The user can use the [-t, --tcb] flag to only validate the tcb contents of the report.
     The user can use the [-s, --signature] flag to only validate the report signature.
+    The user can use the [-m, --measurement] flag to verify that the measurement in the attestation 
+    report matches the expected measurement value (prefix with 0x for hex, without prefix it assumes 
+    decimal values).
+    The user can use the [-d, --host-data] flag to verify that the host-data in the attestation 
+    report matches the expected host-data value (prefix with 0x for hex, without prefix it assumes 
+    decimal values).
+    The user can use the [-r, --report-data] flag to verify that the report-data in the attestation 
+    report matches the expected report-data value (prefix with 0x for hex, without prefix it assumes 
+    decimal values).
+    If the optional flags are not passed, just the signature will be verified.
 
     options:
     -h, --help show a help message
     -p, --processor_model Specify the processor model to use for verification
     -t, --tcb verify the tcb section of the report only
     -s, --signature verify the signature of the report only
+    -m, --measurement provide an expected measurement to verify the measurement field in the attestation report
+    -d, --host-data provide the expected host-data to verify the host-data field in the attestation report
+    -r, --report-data provide the expected report-data to verify the report-data in the attestation report
 
 *snpguest key*::
     usage: snpguest key $KEY_PATH $ROOT_KEY_SELECT [-g, --guest_field_select] [-s, --guest_svn] [-t, --tcb_version] [-v, --vmpl]

Cargo.toml~

@@ -472,13 +472,12 @@ mod attestation {
     fn decode_hex_or_decimal(input: &str) -> Result<Vec<u8>> {
         // Look for "0x" at beginning. If it exists, treat as a hex.
         if let Some(hex_str) = input.strip_prefix("0x") {
-            return Ok(Vec::from_hex(hex_str)?);
-        }
-        else {
+            Ok(Vec::from_hex(hex_str)?)
+        } else {
             Ok(input.as_bytes().to_vec())
         }
     }
-    
+
     fn verify_field(
         field_name: &str,
         expected: &[u8],