NFT improvements

[sneurlax]

Tracking issue used to consolidate my other NFT issues.

See:

• [ ] https://github.com/cypherstack/stack_wallet/issues/648
• [ ] https://github.com/cypherstack/stack_wallet/issues/636
• [ ] https://github.com/cypherstack/stack_wallet/issues/635
• [ ] https://github.com/cypherstack/stack_wallet/issues/634
• [ ] https://github.com/cypherstack/stack_wallet/pull/624

[sneurlax]

The above weren't completed; note the empty checkboxes above. Reference those issues in later commits for tracking purposes.