[Templating] Allows "template" and "parameters" as parameter name (replaces #7908)

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | yes
| Deprecations? | no
| Tests pass?   | yes
| License       | MIT
| Doc PR        | n/a

Allows "template" and "parameters" as parameter name.
**BC break:** These variables were previously declared on every template with respectively the Templating\Storage instance and the array of parameters.