Document How to Configure Spring Security in Eclipse, IntelliJ, and VSCode

[marcusdacoregio]

Some users are having a hard time configuring their environment to work with the Spring Security codebase.

We should review and improve the CONTRIBUTING doc in order to avoid contributors wasting time with stuff like formatting, imports, etc.

See:

• Missing reactive DelegatingRequestMatcherHeaderWriter #11073 (comment)

[marcusdacoregio]

The import order is not fixed automatically, we should provide the IDE configuration or at least mention what is the expected import order:

import java.*
<blank line>
import javax.*
<blank line>
import jakarta.*
import all other imports
<blank line>
import org.springframework.*
<blank line>
import static all other imports