Enable adding extra VM options for the NetBeans language server

[dasTanmoy0096]

Remove bundled default -J heap/GC arguments from the launcher and add a new netbeans.serverVmOptions setting (array) so users can supply additional JVM arguments. The extension reads the setting and prepends each entry with -J when launching the language server; changes trigger a restart. This makes VM options configurable per-machine and avoids forcing defaults. Fixes issues such as:- #16

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