.github: add issue templates

.github/ISSUE_TEMPLATE/bug_report.md

+---
+name: Bug report
+about: Create a bug report
+---
+
+<!-- See https://www.musicpd.org/help/ -->
+## Bug report
+### Describe the bug
+
+
+## Expected Behavior
+
+
+## Actual Behavior
+
+
+## Version
+<!-- Paste the output of "mpd --version" here -->
+
+
+## Log
+<!-- Paste relevant portions of the log file here (--verbose) -->

.github/ISSUE_TEMPLATE/feature_request.md

+---
+name: Feature request
+about: Create a feature request
+---
+
+## Feature request

.github/ISSUE_TEMPLATE/question.md

+---
+name: Question
+about: Ask a question about MPD
+---
+
+<!-- Before you ask a question on GitHub, please read MPD's
+documentation.  A copy is available at
+https://www.musicpd.org/doc/html/ -->
+## Question