Language Server Launch Fixes

[NiklasRentzCAU]

• Running the language server caused a warning: “A terminally deprecated method in sun.misc.Unsafe has been called,” originating from Guava. This commit resolves the issue by upgrading to a newer Guava version and switching Guice to CHILD class loading.
• Launching the language server from Eclipse now uses Maven mechanisms exclusively, rather than P2 dependencies that may also be included by other bundles.
• Resources (icons, META-INF/services directory) are now correctly built by Maven and included in the language server, so the launch configuration only needs to specify the language server itself.
• Two dependencies that were upgraded automatically by Maven with new Eclipse releases, even without changes to this code, have been pinned to avoid signer mismatch errors.

[NiklasRentzCAU]

Reviewed externally.