Moved basics chapters into sub-folder and reformatted config file

chapters/basics/boolean-logic.md

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+Boolean logic is used to combine booleans to return another boolean.
+
+Using double ampersands tells PHP to check if both values are true.
+If so, it will return true. If not, it will return false.
+```php
+<?php
+
+$a = true;
+$b = true;
+$c = false;
+
+$a && $b; // returns true
+$a && $c; // returns false
+```
+
+Using two pipe characters checks if either value is true.
+Then, it will return true. If both values are false, then PHP
+returns false.
+```php
+$a = true;
+$b = false;
+$c = false;
+$d = true;
+
+$a || $b; // returns true
+$b || $c; // returns false
+$a || $d; // returns true
+```
+
+Using an exclamation point returns the opposite value.
+```php
+$d = true;
+echo !$d; // outputs false
+```