Added phpcs config file, useful for moodle-plugin-ci own style

Note that this is the config that I was using here since ages
ago and it aligns 99% with the moodle-cs one.

Basically, it's PSR12 with a few customisations.

phpcs.xml.dist

@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ruleset>
+    <description>The coding rules configuration for the moodle-plugin-ci project.</description>
+
+    <!-- By default, we want to check the src and tests directories -->
+    <file>./src</file>
+    <file>./tests</file>
+
+    <!-- We don't want to analyse these -->
+    <exclude-pattern>*/vendor/*</exclude-pattern>
+    <exclude-pattern>*/moodle/*</exclude-pattern>
+    <exclude-pattern>*/tests/Fixture/*</exclude-pattern>
+    <exclude-pattern>*/tests/*/Fixture/*</exclude-pattern>
+
+    <!-- PSR12 with a few exceptions and adjustments -->
+    <rule ref="PSR12">
+        <exclude name="Squiz.Functions.MultiLineFunctionDeclaration.BraceOnSameLine"/>
+    </rule>
+
+    <!-- Some more chars don't hurt too much -->
+    <rule ref="Generic.Files.LineLength">
+        <properties>
+            <property name="lineLimit" value="132"/>
+            <property name="absoluteLineLimit" value="180"/>
+        </properties>
+    </rule>
+
+    <!-- We want to enforce && and || instead of and and or -->
+    <rule ref="Squiz.Operators.ValidLogicalOperators"/>
+
+    <!-- We want to use always the short array syntax -->
+    <rule ref="Generic.Arrays.DisallowLongArraySyntax"/>
+
+    <!-- We want better commas managing -->
+    <!-- Space after comma -->
+    <rule ref="moodle.WhiteSpace.SpaceAfterComma"/>
+    <!-- Comma at the end of multi-line arrays -->
+    <rule ref="NormalizedArrays.Arrays.CommaAfterLast">
+        <exclude name="NormalizedArrays.Arrays.CommaAfterLast.MissingMultiLineCloserSameLine" />
+    </rule>
+
+    <!--PHPCompatibility configuration-->
+    <rule ref="./vendor/phpcompatibility/php-compatibility/PHPCompatibility/ruleset.xml"/>
+    <config name="testVersion" value="8.1-"/>
+</ruleset>