Breadcrumb API

### Tasks 
- [x] Entity breadcrumb
- [x] Path breadcrumb
- [x] Static breadcrumb
- [x] Dynamic breadcrumb with controller
- [x] [Documentation](/andytruong/at_base/wiki/7.x-2.x-easy-breadcrumb)
- [ ] Documentation for at_fn()
- [ ] Test case

### Example configuration

```yaml
# ---
# file: your_module/config/breadcrumb.yml
# ---
breadcrumbs
  paths:
    'contact-*':
      weight: -100
      breadcrumbs:
        - ['[site:name]', '[site:url]']
        - ['Current page ->[current-page:title]', '[current-page:url]']
        - ['Demo config of @crom_andy']
  entity:
    node:                   # <-- entity type
      page:                 # <-- bundle
        full:               # <-- view mode
          breadcrumbs:      # <-- static breadcrumb
            - ['[site:name]', '[site:url]'] # <-- support tokens
            - ['About', 'about-us']
      article:              # <-- bundle
        full:               # <-- view mode
          controller:       # <-- dynamic breadcrumbs, rendered by a controller.
            - class_name
            - method_name
            - ['%entity', '%entity_type', '%bundle', '%view_mode', '%langcode']
      gallery:              # <-- bundle
        full:               # <-- view mode
          function:  my_fn  # <-- dynamic breadcrumbs, rendered by a controller.
          arguments: [argument_1, argument_2, argument_3]
```