kits: implement external kit dependency resolution

[webern]

Description

Implement the kit dependency resolution algorithm described by https://github.com/bottlerocket-os/twoliter/issues/4. Write the resolved dependencies to Twoliter.lock.

Definition of Done

When Twoliter can resolve all external and local kit dependencies and write this dependency graph to Twoliter.lock.

Depends on:

• [ ] https://github.com/bottlerocket-os/twoliter/issues/4
• [x] https://github.com/bottlerocket-os/twoliter/issues/7
• [ ] https://github.com/bottlerocket-os/twoliter/issues/17
• [ ] https://github.com/bottlerocket-os/twoliter/issues/16

id: kitdepsimpl
epic: kits

Related to https://github.com/bottlerocket-os/bottlerocket/issues/2669