Reimplement --jpms with JPMS module APIs

[sbordet]

Jetty version
10.0.x

Description
Currently, java -jar start.jar --jpms forces the fork of another JVM: the first JVM computes the module-path and the class-path and then passes them as command line options to the second JVM.

This has been done because Jetty 9.4.x is based on Java 8 but could be run in Java 9+, and therefore we could not use the JPMS module APIs.

However, in Jetty 10 we can use the JPMS module APIs, so we should use them to build a ModuleLayer with the right modules and class-path to start Jetty, exactly like we use the ClassLoader APIs to build a ClassLoader with the class-path when we don't use JPMS.

[github-actions]

This issue has been automatically marked as stale because it has been a
full year without activity. It will be closed if no further activity occurs.
Thank you for your contributions.

[github-actions]

This issue has been automatically marked as stale because it has been a
full year without activity. It will be closed if no further activity occurs.
Thank you for your contributions.

[github-actions]

This issue has been automatically marked as stale because it has been a
full year without activity. It will be closed if no further activity occurs.
Thank you for your contributions.

[github-actions]

This issue has been automatically marked as stale because it has been a
full year without activity. It will be closed if no further activity occurs.
Thank you for your contributions.