[2.0.1] Make Componenent element builder alterable

Naming is hard :)

We are allowing the alteration of a slot source value:

  protected function buildSlot(array $build, string $slot_id, array $definition, array $configuration, array $contexts): array {
   ...
    foreach ($configuration["sources"] as $source_configuration) {
      ...
      $source_value = $source->getValue($slot_prop_type) ?? [];
      $this->moduleHandler->alter('component_built', $source_value, $source_configuration);
  }

So, instead of hook_component_built_alter (component_built), we can propose

• hook_component_slot_source_alter (component_slot_source)
• hook_sdc_slot_source_alter (sdc_slot_source)
• hook_ui_patterns_slot_source_alter (ui_patterns_slot_source)
• hook_slot_source_alter (slot_source) if the previous ones are too long

Discussed with Mikael. We are not altering the source but the source value:

• hook_component_slot_value_alter (component_slot_value)
• hook_sdc_slot_value_alter (sdc_slot_value)
• hook_ui_patterns_slot_value_alter (ui_patterns_slot_value)
• hook_slot_value_alter (slot_value) if the previous ones are too long

But I still prefer the "slot_source" one ;)

Thinking aloud: Is it limited to slot sources ? Why not opening this alter to prop sources?

• hook_component_source_value_alter (component_source_value)
• hook_sdc_source_value_alter (sdc_source_value)
• hook_ui_patterns_source_value_alter (ui_patterns_source_value)
• hook_source_value_alter (source_value) if the previous ones are too long