ToJSON: allow custom as_json function

Dependencies

• [2] SYLVCTT6 Start api cleanup with the User model
• [*] LZVO64YG Merge in the first bits of the API work

Change contents

• edit in src/lib/Hydra/Component/ToJSON.pm at line 12
  [4.2603]

  [2.0]
  +

  + if ($self->can("as_json")) {

  + return $self->as_json();

  + }