Create onboarding and offboarding issue templates

[glenflorendo]

Description

This PR creates onboarding and offboarding issue templates to assist in the management of our team.

Related Issues

Resolves #476 Resolves #477

Checklist

• [x] I have followed all conventions outlined in our documentation.
• [x] I have fully tested my changes and confirmed that all new and existing tests pass.
• [x] I have written meaningful commit messages for all changes.
• [x] I have linted and formatted my changes to follow the code style of this repository.
• [x] I have updated our documentation, accordingly.
• [x] I have checked currently opened pull requests to ensure that there are no pending pull request for the same changes or issues.
• [x] I have confirmed that this pull request fully meets the acceptance criteria for all related issues listed above.