Move token information functions to a service

1. +++ b/src/Token.php
   @@ -0,0 +1,192 @@
   +namespace Drupal\token;
   +
   +use Drupal\Core\Utility\Token as TokenBase;
   +
   +class Token extends TokenBase {
   

   Nice work. Lets add an a docblock to the class and define an interface for those additional methods.

2. +++ b/src/Token.php
   @@ -0,0 +1,192 @@
   +  /**
   +   * {@inheritdoc}
   +   */
   +  public function getInfo($token_type = NULL, $token = NULL) {
   

   additional optional is tricky as it's not defined on the original class.

   I think having a service gives us a better way to do this, by having specific accessor methods for this. getTypeInfo($token_type) and getTokenInfo($token_type, $token) for example.

3. +++ b/token.module
   @@ -353,52 +353,11 @@ function token_module_implements_alter(&$implementations, $hook) {
   + *
   + * @deprecated
     */
    function token_get_info($token_type = NULL, $token = NULL) {
   

   wondering how many of those functions we want to keep around.

   I think only very few modules use those API functions, so I'd be OK with removing them.

Fair enough, we can remove the functions in a follow-up. Please create that.

Going through the module, some notes on other functions that we should consider to remove or cleaned up. Not necessarily all the in the same issue...

* token_type_load() seems to be an old D7 menu load callback, can be removed, is the same as getTokenTypeInfo() I think
* token_clear_cache() refers to a number of helper functions for static cache clears, many don't exist anymore.
* token_admin_menu_output_alter(), in case admin_menu ever gets ported to 8.x, it will very likely work very differently, so we should probably just drop it.
* token_form_alter() profile forms don't exist anymore in core, others can maybe be removed too, not sure. See also the related core issue there.
* token_field_widget_form_alter, has a wrong implements hook method name.
* left-over "Implements hook_entity_view_modes_info()"
* maybe token_get_entity_mapping() should be moved to this service too
* token_element_validate_token_context is deprecated
* token_form_system_actions_configure_alter() is unported, forms are called differently and that API function no longer exists