Skip analysis of non-solution files

Some exercises consist of more than one file in the `src/main/java` folder, and some of them are designed to be read-only files. These are marked as such in the exercise's `.meta/config.json` file, because they should be listed in the `files.editor` list.

For example, the [configuration for the `wizards-and-warriors-2` exercise](https://github.com/exercism/java/blob/main/exercises/concept/wizards-and-warriors-2/.meta/config.json) lists the following files as read-only:

- `src/main/java/Character.java`
- `src/main/java/Destination.java`
- `src/main/java/TravelMethod.java`

The goal of this issue is to make sure that read-only files are never processed by the analyzer.

In most cases processing these files may not introduce any issues, but just in case one of them contains code that triggers an analyzer comment we should skip them by default. If not, a student may receive feedback on a file that they did not write and cannot edit, which is just confusing.

从 exercises/concept/wizards-and-warriors-2/.meta/config.json 开始，追踪 analyzer 如何读取其 files.editor 列表。完成标准是：其中标记为只读的文件会被排除在分析之外，而可编辑的解决方案文件仍会继续处理。

由索引模型根据 Issue 内容生成。