Add Gradle instructions and instruction selector to package details

What does this MR do?

This MR picks up where !55604 (merged) left and finalize the implementation of the installation instruction switch and adds the gradle instructions

Description	MR
Add new component, fix multiline label	!55604 (merged)
Wire new component in all package managers	👈 you are here

Screenshots (strongly suggested)

Composer	Conan	Maven	NPM	Nuget	PyPi

Maven focus

Gradle

Maven

Screencap for Maven (old copy for gradle commands)

MavenToGradleRefresh

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because _____.
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team

Related to #207467 (closed)