unoccluded navmesh snap multiple ignores

[aclegg3]

Motivation and Context

This PR refactors navmesh_utils to allow multiple object_id ignores in the "unoccluded snap" and accessibility utils.

This change has become more important with increased use of articulated objects and agents where the ignore list should include both the agent's body/links, the target object, and possibly additional links of a particular furniture asset.

How Has This Been Tested

Refactor should be mostly transparent beyond the conversion of inputs to lists. CI tests should satisfy.

Types of changes

• [Refactoring] Large changes to the code that improve its functionality or performance
• [Development] A pull request that add new features to the habitat-lab task and environment codebase. Development Pull Requests must be small (less that 500 lines of code change), have unit testing, very extensive documentation and examples. These are typically new tasks, environments, sensors, etc... The review process for these Pull Request is longer because these changes will be maintained by our core team of developers, so make sure your changes are easy to understand!

Checklist

• My code follows the code style of this project.
• I have updated the documentation if required.
• I have read the CONTRIBUTING document.
• I have completed my CLA (see CONTRIBUTING)
• I have added tests to cover my changes if required.

[0mdc]

LGTM!