Summary:
The Clazy plugin relies on the project providing a buildsystem manager
to query for the toplevel build directory. If a project has no such manager,
showing the Clazy plugin config pages in the project settings has no
purpose.
As a session might contain different projects, some with a buildsystem
manager, some without, simply disabling the Clazy plugin might not be
wanted for the projects with a buildsystem manager.
So we need to have some condition whether to show some plugins per-project
config pages or not.
For a start, motivated by the crash with the Clazy plugin which has a
hard assumption of project->buildSystemManager() being != nullptr,
this patch adds to the code to collect the config pages for the project
settings dialog some special code which makes use of the plugin metadata
to skip plugins which require a org.kdevelop.IBuildSystemManager, if
there is no buildsystem manager available for the project.
As well adds the (so far missing) entry
X-KDevelop-IRequired: [org.kdevelop.IBuildSystemManager]
to the metadata.

BUG: 400769

Test Plan:
Clazy config is no longer shown in the project settings dialog if the
project is used with the generic project manager.

Reviewers: #kdevelop, apol

Reviewed By: #kdevelop, apol

Subscribers: kfunk, kdevelop-devel

Tags: #kdevelop

Differential Revision: https://phabricator.kde.org/D16915