Support for SSL/TLS protected connections to MySQL databases (#14142)

* Allow configuration of the SSL/TLS operating mode when connecting to a mysql database

* Support SSL/TLS DB connections in the dispatcher service as well

* Apply black formatting standards to Python files

* Suppress pylint errors as redis module is not installed when linting

* More pylint fixes

* Correct typo in logging output

* Refactor SSL/TLS changes into DBConfig class instead of ServiceConfig

* Define DB config variables as class vars instead of instance vars

* Break circular import

config/database.php

@@ -66,6 +66,7 @@ return [
             'prefix_indexes' => true,
             'strict' => true,
             'engine' => null,
+            'sslmode' => env('DB_SSLMODE', 'disabled'),
             'options' => extension_loaded('pdo_mysql') ? array_filter([
                 PDO::MYSQL_ATTR_SSL_CA => env('MYSQL_ATTR_SSL_CA'),
             ]) : [],