Introduce VS Code/JDTLS formatter scheme

[CsCherrYY]

requires https://github.com/eclipse/eclipse.jdt.ls/pull/2589

This PR introduces a VS Code/JDTLS formatter scheme, which can be configured without existing eclipse profile.

Deprecate configurations:

• java.format.settings.url
• java.format.settings.profile

New configurations:

• java.format.scheme

The configuration accepts both two kinds of values: "string" and "object".

String

Directly configure the formatter scheme. The default value is eclipse, some popular scheme like google can be introduced in the future.

example:

"java.format.scheme": "eclipse"

Object

Configure the formatter scheme. It has 4 properties:

• "style": Configure the formatter scheme. The default value is eclipse, some popular scheme like google can be introduced in the future.
• "path": Has the same functionality as previously java.format.settings.url, will be ignored if the current style is not eclipse.
• "profile": Has the same functionality as previously java.format.settings.profile, will be ignored if the current style is not eclipse.
• "configurations": The custom formatter configurations, which will take precedence over the corresponding settings in the scheme, will be ignored if the current style is not eclipse.

example1: Use default eclipse configuration, but set the brace position of blocks to next line:

 "java.format.scheme": {
    "style": "eclipse",
    "configurations": {
      "brace.position.for.block": "nextLine"
    }
}

example2: Use custom eclipse configuration in profile custom from file .vscode/java-formatter.xml, but set the brace position of blocks to next line:

 "java.format.scheme": {
    "style": "eclipse",
    "path": ".vscode/java-formatter.xml",
    "profile": "custom",
    "configurations": {
      "brace.position.for.block": "nextLine"
    }
}

Configurations list

The first version of the configurations list would be the settings mentioned in formatter related issues in https://github.com/redhat-developer/vscode-java and https://github.com/eclipse/eclipse.jdt.ls, they would be easily configured by the users so that we expose them to convenient editing.

We can also expand the list if there are requests.