Psalm: switch from Phive to Composer

This switches the installation method for Psalm from Phive to Composer, while still using a Phar file for running Psalm.

Includes:
* Removing Psalm from the Phive configuration.
* Adding Psalm to the Composer configuration. Includes upgrading from version `3.11.2` to version `4.8.1`.
* Adjusting the script used in the `Makefile`.
    👉 Please verify and test this as things work differently on different OS-es and this should work for you.
* Adjusting the GH Actions script to use the Composer installed version of Psalm.

Note: due to the committed `composer.lock` file, Psalm will not automatically upgrade when newer versions are available.

Refs:
* https://github.com/vimeo/psalm/releases
* https://github.com/psalm/phar/releases

.github/workflows/push.yml

@@ -188,7 +188,6 @@ jobs:
         with:
           php-version: ${{ matrix.php-versions }}
           extensions: ${{ env.extensions }}
-          tools: psalm
           ini-values: memory_limit=2G, display_errors=On, error_reporting=-1
 
       - name: Install Composer dependencies & cache dependencies
@@ -197,7 +196,7 @@ jobs:
           composer-options: --optimize-autoloader
 
       - name: Run psalm
-        run: psalm --output-format=github
+        run: vendor/bin/psalm.phar --output-format=github
 
 
   bc_check: