using tpm to store node identity seed

[muhamadazmy]

Depends on #1787

This will does the following:

• For nodes that has tpm, use tpm to store node seed
• Nodes without tpm, will continue use a file on disk
• Nodes that already has a key file, will move that key to tpm and delete the key if the node has tpm

This PR uses the tpm2 utils. The branch and build and install tpm is not merged yet.