docs: move Controller recipes to how-to guides

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At the moment, the [Controllers](https://loopback.io/doc/en/lb4/Controllers.html) page in "Behind the scenes" is mixing [explanations](https://documentation.divio.com/explanation/) with [how-to guides](https://documentation.divio.com/how-to-guides/). This makes it difficult for our users to find the relevant content (a recipe to achieve the outcome they want).

As part of our adoption of the four-quadrant documentation system (see #5549 and #5718), we should extract all guides from explanation pages into guide pages (see #5768 for inspiration) and keep explanation pages focused on explaining the concepts & providing background information.

This story is a part of Epic #5783 move recipes to how-to guides.

## Acceptance criteria

Move the following recipes into "How-to guides", decide yourself whether to create a new page for each recipe or group multiple recipes in one page.

- [ ] [How to allow parameterized decorations](https://loopback.io/doc/en/lb4/Controllers.html#class-factory-to-allow-parameterized-decorations)
- [ ] [How to define controller classes at runtime](https://loopback.io/doc/en/lb4/Controllers.html#creating-controllers-at-runtime)
- [ ] [How to report a custom error from a controller method](https://loopback.io/doc/en/lb4/Controllers.html#handling-errors-in-controllers)

Consider adding a "Common tasks" section to "Application" page, it should list pointers to new how-to guides. See [Server >> Common tasks](https://loopback.io/doc/en/lb4/Server.html#common-tasks) for inspiration.

Start with the Controllers page and identify the three linked recipes that need to move into How-to guides. Review the Application page and Server > Common tasks for the intended pointer structure, along with issues #5549, #5718, #5768, and #5783. Done means the recipes are moved, Controllers remains focused on explanations, and relevant links and checklists are updated.

Written by the indexing model from the issue text.