[feature] Add securemode, verifySIDPassword

[hMcLauchlan]

Hello!

Thank you for working on this utility. Please find in this PR some patches which we've carried on top of master to enable our use cases (particularly around setting passwords on SEDs). They should be generic enough to be mainline'd, but I'm happy to make changes as appropriate.

This PR does two main things:

• Fixup and modify (where appropriate) #271, bringing it up-to-date with master.
• Add a utility verifySIDPassword, which does what it sounds like it does.

Please see commit messages for more details. Thanks!

Edit: Forgot to post my test plan:

[root@host~]# ./sedutil-cli -s -v -n --setSIDPassword /dev/nvme0n1
Log level set to DBG 
sedutil version : 
No password hashing incompatible with secure mode
Disabling password hashing in secure mode (-s)

Please enter password ***********************************Unknown Feature in Discovery 0 response 402
Unknown Feature in Discovery 0 response 402
Performing setSIDPassword 

Please enter the new password ***

Please confirm the new password ***   
[root@host ~]# ./sedutil-cli -s -v -n --verifySIDPassword /dev/nvme0
Log level set to DBG 
sedutil version : 
No password hashing incompatible with secure mode
Disabling password hashing in secure mode (-s)

Please enter password ***Unknown Feature in Discovery 0 response 402
Unknown Feature in Discovery 0 response 402
Performing verifySIDPassword 
Successfully verified SIDPassword
[root@host ~]# ./sedutil-cli -s -v -n --setSIDPassword /dev/nvme0n1 
Log level set to DBG 
sedutil version : 
No password hashing incompatible with secure mode
Disabling password hashing in secure mode (-s)

Please enter password ***Unknown Feature in Discovery 0 response 402
Unknown Feature in Discovery 0 response 402
Performing setSIDPassword 

Please enter the new password ***********************************

Please confirm the new password ***********************************
[root@host~]# ./sedutil-cli -s -v -n --verifySIDPassword /dev/nvme0
Log level set to DBG 
sedutil version : 
No password hashing incompatible with secure mode
Disabling password hashing in secure mode (-s)

Please enter password ***********************************Unknown Feature in Discovery 0 response 402
Unknown Feature in Discovery 0 response 402
Performing verifySIDPassword 
Successfully verified SIDPassword