Use client agnostic command names

From https://github.com/eclipse/eclipse.jdt.ls/pull/424#issuecomment-344130840, I noticed the debugger exposes vscode* commands on the server side.

[Trace - 21:52:28] Received request 'client/registerCapability - (5)'.
Params: {
    "registrations": [
        {
            "id": "18163e21-97e7-4ae8-b51c-5cdb20e639b1",
            "method": "workspace/executeCommand",
            "registerOptions": {
                "commands": [
                    "java.edit.organizeImports",
                    "vscode.java.fetchUsageData",
                    "vscode.java.resolveClasspath",
                    "vscode.java.resolveMainClass",
                    "vscode.java.updateDebugSettings",
                    "vscode.java.buildWorkspace",
                    "vscode.java.startDebugSession"
                ]
            }
        }
    ]

It'd be better if the names were client agnostic.

首先定位列出的 workspace/executeCommand 名称在哪里注册和使用，包括 issue 中显示的 vscode.java.* 命令。确定项目的客户端无关命名约定，以一致的方式更新注册项和引用，并验证命令注册对 Java 调试服务器仍然有效。