FEAT - Make a github issue template for audits

[tonyfast]

An auditor should be able to come to this site and open an issue with a template that provides the list minimum information required to achieve a fix. fortunately, @manfromjupyter has set a great standard to record issues that we can act on. maybe we can take some exemplar issues & come up with a good issue template to put in this repo.

according to github we can put the issue template in the docs folder which seems more transparent than .github. so i think we'd wind up with docs/issue_template.md

Target -> https://github.com/jupyterlab/.github/tree/master/.github/ISSUE_TEMPLATE

[isabela-pf]

I've set up issue templates on repos before, so I'm happy to support working on this! Good idea!

[trallard]

Will mark this as on - hold until we sort out #86 but I think this would be a great addition as and a complement to the testing scripts we are working on

[isabela-pf]

On a related but more scoped note, I've been working on a draft review checklist for theming accessibility. For the larger scale discussion, quansight-labs/jupyter-a11y-mgmt #133 is the place to be. @trallard asked me to add this.

[trallard]

Marking as in progress as the work is being done as part of the checklist and theming work