Added ECS and PHPStan

With helper batch files

php/cc.bat

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+composer check-cs 

php/ecs.yaml

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+parameters:
+    sets:
+        - 'psr12'
+        - 'php71'
+        - 'symplify'
+        - 'common'
+        - 'clean-code'
+
+    line_ending: "\n"
+
+    # 4 spaces
+    indentation: "    "

php/fc.bat

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+composer fix-cs 

php/phpstan.neon

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+includes:
+    - vendor/symplify/phpstan-extensions/config/config.neon
+    - vendor/phpstan/phpstan-phpunit/extension.neon
+
+parameters:
+    paths:
+        - src
+        - tests
+
+    # The level 8 is the highest level
+    level: 8
+
+    # Larstan recommendation:
+    checkMissingIterableValueType: false
+
+    ignoreErrors:
+
+    # buggy
+
+    # mixed
+
+    # cache buggy
+
+    # tests
+
+    # iterable

php/ps.bat

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+composer phpstan 

php/pu.bat

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+composer test