chore: Add MegaLinter and linters' configs

MegaLinter config and linter configs for:
- Dockerfiles
- Editorconfig checker
- Groovy
- Markdown
- Python
- Shell scripts
- Yaml files

Resolves #17

.groovylintrc.json

@@ -0,0 +1,25 @@
+{
+  "extends": "recommended",
+  "rules": {
+    "basic.DeadCode": "off",
+    "comments.ClassJavadoc": "off",
+    "convention.CompileStatic": "off",
+    "convention.MethodReturnTypeRequired": "off",
+    "convention.NoDef": "off",
+    "convention.VariableTypeRequired": "off",
+    "formatting.ClassStartsWithBlankLine": "info",
+    "formatting.ConsecutiveBlankLines": "off",
+    "groovyism.ExplicitCallToEqualsMethod": "off",
+    "groovyism.GStringExpressionWithinString": "off",
+    "naming.FactoryMethodName": "off",
+    "naming.VariableName": "off",
+    "serialization.SerializableClassMustDefineSerialVersionUID": "info",
+    "size.NestedBlockDepth": {
+      "maxNestedBlockDepth": 10
+    },
+    "unnecessary.UnnecessaryGetter": "off",
+    "unused.UnusedVariable": {
+      "ignoreVariableNames": "_"
+    }
+  }
+}

.hadolint.yaml

@@ -0,0 +1,6 @@
+---
+##########################
+## Hadolint config file ##
+##########################
+ignored:
+  - DL3018

.markdownlint.json

@@ -0,0 +1,9 @@
+{
+  "heading-style": {
+    "style": "atx"
+  },
+  "line-length": {
+    "line_length": 120
+  },
+  "no-multiple-blanks": false
+}

.mega-linter.yaml

@@ -0,0 +1,32 @@
+ENABLE_LINTERS:
+  - BASH_SHELLCHECK
+  - DOCKERFILE_HADOLINT
+  - EDITORCONFIG_EDITORCONFIG_CHECKER
+  - GROOVY_NPM_GROOVY_LINT
+  - MARKDOWN_MARKDOWNLINT
+  - PYTHON_BLACK
+  - YAML_YAMLLINT
+
+# npm-groovy-lint configuration
+GROOVY_NPM_GROOVY_LINT_FILE_EXTENSIONS:
+  - .dsl
+  - .gradle
+  - .groovy
+  - .Jenkinsfile
+GROOVY_NPM_GROOVY_LINT_FILE_NAMES_REGEX:
+  - Jenkinsfile$
+GROOVY_NPM_GROOVY_LINT_ARGUMENTS: --failon error
+
+# editorconfig checker configuration
+EDITORCONFIG_EDITORCONFIG_CHECKER_FILTER_REGEX_EXCLUDE: >
+    (?x) ^gradlew | ^\.idea/.* | ^test/resources/callStacks/.*
+
+# general options
+CLEAR_REPORT_FOLDER: true
+PRINT_ALL_FILES: true
+PRINT_ALPACA: false
+SHOW_ELAPSED_TIME: true
+
+# reporter options
+CONFIG_REPORTER: false
+UPDATED_SOURCES_REPORTER: false

.yamllint.yml

@@ -0,0 +1,17 @@
+---
+###########################################
+# These are the rules used for            #
+# linting all the yaml files in the stack #
+# NOTE:                                   #
+# You can disable line with:              #
+# # yamllint disable-line                 #
+###########################################
+extends: default
+rules:
+  new-lines:
+    level: warning
+    type: unix
+  line-length:
+    max: 500
+  comments:
+    min-spaces-from-content: 1 # Used to follow prettier standard: https://github.com/prettier/prettier/pull/10926