Function dependency inventory

[awasyn]

Function Inventory

This commit includes an Rmd file with the function inventroy and saved visualization of the functions which can be
opened and manipulated in a browser. There are also handy functions to navigate the graph but you can also scroll
and zoom in.

I wasn't sure if we wanted to include the inventory in pages(package site) so I put it in the inst/ sub-directory not to be rendered on CI.
But i am open to making changes as needed.

What kind of change(s) are included?

Response to #3

• Feature (adds or updates new capabilities)
• Fixes an issue.
• Enhancement (adds functionality).

Checklist

Please ensure that all boxes are checked before indicating that this pull request is ready for review.

• I have read and followed the CONTRIBUTING.md guidelines.
• I have searched for existing content to ensure this is not a duplicate.
• I have performed a self-review of these additions (including spelling, grammar, and related).
• I have added comments to my code to help provide understanding.
• I have added a test which covers the code changes found within this PR.
• I have deleted all non-relevant text in this pull request template.
• Reviewer assignment: Tag a relevant team member to review and approve the changes.

@jananiravi @the-mayer