Add TTP Parser with local ttp templates, with overrides in git repo

[jeffkala]

Environment

• Nautobot version: 2.3+
• nautobot-device-onboarding version: next

Proposed Functionality

All for the yaml file to support ttp parsers. The idea would be to have the following.

Add parser options for ttp. The ttp parser should have the following lookups.

1. Look in the core source code for a parsers/ttp directory, where the template should be named <network_driver>_<command>.ttp.
2. If the file is not found based on this lookup, search the Gitrepo command_mappers/ttp/<network_driver>_<command>.ttp.
3. Add TTP parser (manually) meaning don't use the use_ttp feature in netmiko. This will follow the same pattern as textfsm does today.

Optionally:
It may make sense during this same feature request to also add parsers/textfsm in order to support textfsm template overrides.

Use Case

TTP is a parsing option that is growing in popularity. It may offer easier ways to extend this app to support additional platforms.

[jeffkala]

Done in #275