Add: support for astropy and other partners in the parse issue method

[lwasser]

Right now parse issues returns issue metadata.
We haven't until now needed to parse partner data.

I have updated the sunpy review here with the format that i'd like the new issue template to look like.

We will want to parse that ## Community partners section and pull any partner information into a list that we can parse on our website (and that partners can parse as well).

Steps

• first add "get_partners" to the issue parse workflow & create tests for it working as expected in various cases
• Then add get_partners as a part of the contributor workflow to add partner data to contribs + tests