docs(maintainers): introduce Code Owner and Reviewer maintainer types (#27010)

Split the maintainer role into two types to make it easier to grow the
bench without asking new contributors to commit to a specific component
up front. Code Owners keep their existing scoped responsibility for a
category, while Reviewers help across the project without ownership of
any specific area. Both are full maintainers, share the @PX4/dev-team
GitHub team, and have the same write access and voting rights.

Rename the Active Maintainers table to Code Owners with no change to
the current roster. Add an empty Reviewers table so future nominations
land in their own PRs. Update the contributor docs to describe the two
types, cover both in the recruitment and onboarding flow, and note the
promotion path from Reviewer to Code Owner.

Signed-off-by: Ramon Roche <mrpollo@gmail.com>

docs/en/contribute/dev_call.md

@@ -7,7 +7,7 @@ const { site } = useData();
 
 <div v-if="site.title !== 'PX4 Guide (main)'">
   <div class="custom-block danger">
-    <p class="custom-block-title">This page may be out of date. <a href="https://docs.px4.io/main/en/contribute/dev_call">See the latest version</a>.</p>
+    <p class="custom-block-title">This page may be out of date. <a href="/en/contribute/dev_call.md">See the latest version</a>.</p>
   </div>
 </div>
 
@@ -15,8 +15,8 @@ The PX4 dev team and community come together to discuss any topic of interest to
 
 ## Who should attend?
 
-- Core project maintainers
-- Component maintainers
+- Code Owners
+- Reviewers
 - Test team lead
 - Dronecode members
 - Community members (you!)