Adding and adjusting repo issue templates

[langsmith]

This pr adjusts and adds to the issue template folder in this repo. #1024 has a fleshed-out release checklist, which explains how to tie Java releases into the Maps/Navigation SDKs. I figured it'd be good to have the checklist as a formal issue template.

cc @mapbox/maps-android

[langsmith]

Don't review yet. We need to figure out ideal process. Release should be done via Github tags, right?

Creating https://github.com/mapbox/mapbox-java/releases/tag/v4.9.0-alpha.1 didn't kickstart the CircleCI release job.

I guess because of https://github.com/mapbox/mapbox-java/blob/master/circle.yml#L48-L49. Should https://github.com/mapbox/mapbox-java/blob/master/circle.yml#L48-L49 be changed to only [[ $CIRCLE_TAG == v* ]] ?

To get 4.9.0-alpha.1 to Bintray, I had to change mentions of master to my release branch name in circle.yml.

[LukasPaczos]

@langsmith checkout those PRs I made a couple of weeks ago adjusting the mapbox-gestures-android to be bintray/tag-release compatible because I see mapbox-java is going to suffer from similar issues:

• Run tag release jobs on CI mapbox-gestures-android#81
• Fixup stable Bintray publication mapbox-gestures-android#83
• Fixup automated version name generation script mapbox-gestures-android#84

[langsmith]

Ok @LukasPaczos , this is ready for another round of 👀

[LukasPaczos]

LGTM