Add first-class hardware wallet support

[john-light]

I feel uncomfortable every time I use Blockstack Browser because I have to enter my seed phrase into my browser every time I use it. I would like to see first-class hardware wallet support added to the browser. This means that keys generated on my hardware wallet would be used to:

• Own names
• Pay for transactions
• Sign/decrypt data for each of the Blockstack apps I use

This could also eliminate the awkward UX where I have to enter a password every time I want to do something.