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

.editorconfig

@@ -1,4 +1,16 @@
+root = true
+
+[*]
+end_of_line = lf
+charset = utf-8
+insert_final_newline = true
+trim_trailing_whitespace = true
+
 # Override for Makefile
 [{Makefile, makefile, GNUmakefile}]
 indent_style = tab
 indent_size = 4
+
+[*.{yml.yaml,json}]
+indent_style = space
+indent_size = 2