dev: add GitHub detailed issue templates (#1591)

* dev: add GitHub detailed issue templates

* dev: update PR template

contributing guidelines link is already in PR UI

changelog message is no longer needed -- it is generated from commit messages

* dev: use bug report template on CMS crash

* Update bug_report.md

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,45 @@
+---
+name: Bug report
+about: Report a problem you are experiencing
+
+---
+
+<!--
+If you are reporting a new issue, make sure that we do not have any duplicates already open. You can ensure this by searching the issue list for this repository. If there is a duplicate, please add a comment to the existing issue instead.
+
+Please include as much of the information requested below as possible. If you fail to provide the requested information within 7 days, we cannot debug your issue and will close it. We will, however, reopen it if you later provide the information.
+
+If you have an issue that can be shown visually, please provide a screenshot or GIF of the problem as well.
+-->
+
+**Describe the bug**
+A clear and concise description of what the bug is.
+
+**To Reproduce**
+Steps to reproduce the behavior:
+1. Go to '...'
+2. Click on '....'
+3. Scroll down to '....'
+4. See error
+
+**Expected behavior**
+A clear and concise description of what you expected to happen.
+
+**Screenshots**
+If applicable, add screenshots to help explain your problem.
+
+**Applicable Versions:**
+<!-- You can find the CMS version by checking your web browser's developer tools console while in the CMS. -->
+ - Netlify CMS version: [e.g. 2.0.4]
+ - Git provider: [e.g. GitHub, BitBucket]
+ - OS: [e.g. Windows 7]
+ - Browser version [e.g. chrome 22, safari 11]
+<!-- If using NPM: -->
+ - Node.JS version:
+
+**CMS configuration**
+Please link or paste your CMS `config.yml` here.
+
+
+**Additional context**
+Add any other context about the problem here.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,21 @@
+---
+name: Feature request
+about: Suggest an idea for this project
+
+---
+
+<!--
+Please make sure that we do not have any requests for this feature already open. You can ensure this by searching the issue list for this repository. If there is a duplicate, please add a comment to the existing issue instead.
+-->
+
+**Is your feature request related to a problem? Please describe.**
+A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+
+**Describe the solution you'd like**
+A clear and concise description of what you want to happen.
+
+**Describe alternatives you've considered**
+A clear and concise description of any alternative solutions or features you've considered.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.