Update core git config files, vendor installs for unit testing

Update .gitattributes with more files to ignore
Add .gitignore for php unit test cache
Install dotenv file parser for unit testing
Update current test pages with dotenv file parser (replaces function
call)

Documentation PHPdoc update for checkMe method call

vendor/gullevek/dotenv/psalm.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0"?>
+<psalm
+    errorLevel="8"
+    resolveFromConfigFile="true"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+>
+    <projectFiles>
+        <directory name="src" />
+        <ignoreFiles>
+            <directory name="vendor" />
+            <directory name="test" />
+        </ignoreFiles>
+    </projectFiles>
+</psalm>