Implement kli listen command

[arilieb]

Feature request description/rationale

Writing a keripy listener to support HealthKERI plugin functionality.

• Unlock a local hab and return true or false
• List identifiers in a given, unlocked hab
• Sign data with a selected identifier

Write this as a package. Use client.py in fortress to test. Does not need name and alias, should be run with 'kli listen'. Look at other kli commands for inspiration.

[arilieb]

Implemented: #852

[arilieb]

Spoke too soon, command and package rely on hio uxd server support. See https://github.com/pfeairheller/hio/blob/feat-uxd-server/src/hio/core/uxd/serving.py