Update docs, file formatting and docker images (#766)

* docs: fix wrong licence link

* fix: add more formatting settings, reformat all

feat: add vscode extensions recommendations

* docs: update contributing documentation

* fix: remove unnecessary comment

it was due to broken checkout

* docs: rework installation section

it has been brought up few times, new style should be easier
to understand

* docs: update images provided by catthehacker

* docs: replace 18.04 with recent image

* fix: add final new line

.github/ISSUE_TEMPLATE/feature_template.md

@@ -3,7 +3,7 @@ name: Feature request
 about: Use this template for requesting a feature/enhancement.
 title: "Enhancement: "
 labels: "kind/feature-request"
-assignees: ''
+assignees: ""
 ---
 
 ## Describe feature

.github/ISSUE_TEMPLATE/issue_template.md

@@ -3,7 +3,7 @@ name: Issue
 about: Use this template for reporting a bug/issue.
 title: "Issue: <shortly describe issue>"
 labels: kind/bug
-assignees: ''
+assignees: ""
 ---
 
 <!--