Add Navigator module

[cbkerr]

Description

Displays links to jobs differing in one state point parameter.

Motivation and Context

Makes it easier to view similar jobs and explore the signac project.

Checklist:

• [x] I am familiar with the Contributing Guidelines.
• [x] I agree with the terms of the Contributor Agreement.
• [x] The changes introduced by this pull request are covered by existing or newly introduced tests.
• [x] The package documentation and framework documentation in signac-docs are up to date with these changes.
• [x] I have updated the changelog and added any related issue and pull request numbers for future reference.

[codecov[bot]]

Codecov Report

Merging #188 (c637ce6) into main (c4e2caf) will increase coverage by 1.48%. The diff coverage is 72.94%.

@@            Coverage Diff             @@
##             main     #188      +/-   ##
==========================================
+ Coverage   68.50%   69.98%   +1.48%     
==========================================
  Files          20       21       +1     
  Lines         816      883      +67     
  Branches      113      159      +46     
==========================================
+ Hits          559      618      +59     
- Misses        218      220       +2     
- Partials       39       45       +6     

Files Changed	Coverage Δ
signac_dashboard/util.py	60.00% <26.66%> (+7.61%)	:arrow_up:
signac_dashboard/modules/navigator.py	82.35% <82.35%> (ø)
signac_dashboard/dashboard.py	67.55% <100.00%> (ø)
signac_dashboard/modules/__init__.py	100.00% <100.00%> (ø)

[cbkerr]

I replaced the hacky workaround for comparing lists in the state point to tuples gotten from schema by using the internal utility function _to_hashable. Ready for final review!