Deprecations

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #12625, #12605, #12628, #12622, #12642, #12609, #12651, #12604,  #12607, #12667, #12648
| License       | MIT
| Doc PR        | -

Cherry-picking some pending PRs to make them move forward
this will autoload the referenced class or not? and thus trigger the deprecation even when the constant is no used at all?!