This is a refactoring PR which intends to:

- Reorganize and rename `Behavior` templates so that it is more clear what
  purpose a specific template has.
  There are 3 types of template per `Behavior`:
  - `command` template: it should include nodes that are required by the
    `Behaviors engine` to mount a `Behavior` when it is inserted for the first
    time (`blueprint`). It is most often rendered by the `wysiwyg` when the
    user types a `/command` in the editor and is not rendered by `Owl`.
  - `Component` template: used by `Owl` to populate the `anchor` of a `Behavior`
    (which is the `parent` node of the `command` template)
  - non-protected "content" templates: rendered manually during the lifecycle of
    the `Behavior` `Component`. Those are rendered manually without `Owl`,
    because they can be altered by the collaboration (since they are
    `data-protected="false"`) and `Owl` does not support that the nodes it
    rendered be altered by something else than itself (will crash).

- Reorganize the js code of `Behavior` components and the `HtmlField` patch, so
  that there is some consistency between them and a foreign reader can better
  understand their structure.

- Refactor and rename `updateBehaviors` into `mountBehaviors` because the
  function is becoming quite long and complex, and handles some side effects in
  a pretty ugly way. Notably:
  - add some utils for common/complex use cases
  - add a `validator` object to formalize cases where a `Behavior` mounting can
    become obsolete
  - display warning messages upon `Behavior` `mount` failure only in debug mode

Read more details in each commits.

task-3383561