Update issue/PR templates, contributing.rst, CI

- Keep documentation in sync with master branch

- Run PyLint and MyPy on Github Actions

- Update Issue templates, enforce usage of issue templates, add links to
  resources in Instaloader Documentation

- Update contributing.rst

.github/ISSUE_TEMPLATE/bug_report.md

@@ -24,4 +24,4 @@ If applicable, add error messages and tracebacks to help explain your problem.
 **Additional context**
 Add any other context about the problem here.
 
-(please also see https://instaloader.github.io/contributing.html for how to report a bug)
+<!-- please also see https://instaloader.github.io/contributing.html for how to report a bug -->

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,11 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Contributing to Instaloader
+    url: https://instaloader.github.io/contributing.html
+    about: Guidelines for how to report an issue.
+  - name: Instaloader Troubleshooting
+    url: https://instaloader.github.io/troubleshooting.html
+    about: Many common problems and their workarounds are described here.
+  - name: Instaloader Documentation
+    url: https://instaloader.github.io/
+    about: Many questions might be already answered here.

.github/ISSUE_TEMPLATE/feature_request.md

@@ -15,10 +15,10 @@ A clear and concise description of what you want to happen.
 A clear and concise description of any alternative solutions or features you've considered.
 
 **If the feature request is accepted, would you be willing to submit a PR?**
-
-Yes / No _(Help can be provided if you need assistance submitting a PR)_
+Yes / No
+<!-- Help can be provided if you need assistance submitting a PR -->
 
 **Additional context**
 Add any other context about the feature request here.
 
-(please also see https://instaloader.github.io/contributing.html for how to suggest a feature)
+<!-- please also see https://instaloader.github.io/contributing.html for how to suggest a feature -->

.github/ISSUE_TEMPLATE/question.md

@@ -6,3 +6,7 @@ labels: question
 ---
 
 Your question here...
+
+<!-- Please see our documentation: https://instaloader.github.io/ -->
+
+<!-- Basic questions regarding Instaloader's usage might be more appropriate to ask on Stack Overflow -->