RulesDX for adding actions and conditions

gistfile1.php

<?php
// Existing PR: https://github.com/fago/rules/pull/134/files
$rule->addCondition('rules_test_string_condition', [
  'context_mapping' => ['text:select' => 'node:uid:0:entity:name:0:value'],
  ]));
]);

// With value object:
$rule->addCondition('rules_test_string_condition', ContextConfig()
  ->map('text', 'node:uid:0:entity:name:0:value')
));
// More options:
$rule->addCondition('example', ContextConfig()
  ->map('user', 'node:author')
  ->map('user2', 'node2:author')
  ->setContextValue('text', 'some-text')
  ->process('text', 'uppercase_data_processor_plugin', $optional_processor_config_array)
  ->setConfigKey('only-for-extra-config-used-by-some-plugins', $value)
  ->negateResult()
));

// Then addCondition() can just do: $context_config->toArray() and instantiate the expression.
// ContextConfig methods can check provided values for sanity / conflicts and throw exceptions as necessary.
// addCondition(), addAction() and addExpression() can all take the ContextConfig class as parameter
// Validation of ContextConfig can be done by ContextConfig::checkConfig($expression), to be invoked by the add*() methods

// Create via __invoke()
$config = ContextConfig();
// Create via method.
$config = ContextConfig::create();
// or from array:
ContextConfig::create($values)
  ->checkConfig();