ci: replace superlinter with megalinter (#923)

* ci: replace superlinter with megalinter

Signed-off-by: hackercat <me@hackerc.at>

* fix: apply lint recommendations

Signed-off-by: hackercat <me@hackerc.at>

.mega-linter.yml

@@ -0,0 +1,17 @@
+---
+APPLY_FIXES: none
+DISABLE:
+  - ACTION
+  - BASH
+  - COPYPASTE
+  - DOCKERFILE
+  - GO
+  - JAVASCRIPT
+  - SPELL
+DISABLE_LINTERS:
+  - YAML_YAMLLINT
+  - MARKDOWN_MARKDOWN_TABLE_FORMATTER
+FILTER_REGEX_EXCLUDE: .*testdata/*
+MARKDOWN_MARKDOWNLINT_CONFIG_FILE: .markdownlint.yml
+PARALLEL: false
+PRINT_ALPACA: false