Provide a better support for Quarkus property value

[angelozerr]

Completion for properties value works for boolean (true, false) and enums. But for other case (ex : Level class for log Quarkus properties), it doesn't work.

The idea of this issue is to augment the properties values with a JSON settings (ex: for Level class,values are DEBUG, SEVERE, etc)

The Quarkus LS can provide a JSON settings by default about the properties values and user could extend it to add another values (ex : it adds a new Level).

[angelozerr]

Here my idea how to configure level, driver and datasource url with JSON:

[
	{
		"for": [
			{
				"type": [
					"java.util.logging.Level"
				]
			}
		],
		"values": [
			{
				"name": "DEBUG",
				"docs": "Debug level"
			},
			{
				"name": "INFO",
				"docs": "Info level"
			}
		]
	},
	{
		"for": [
			{
				"name": [
					"quarkus.datasource.driver",
					"quarkus.datasource.{*}.driver"
				]
			}
		],
		"values": [
			{
				"implements": [
					"java.sql.Driver",
					"java.sql.DataSource"
				]
			}
		]
	},
	{
		"for": [
			{
				"name": [
					"quarkus.datasource.url",
					"quarkus.datasource.{*}.url"
				]
			}
		],
		"values": [
			{
				"when": {
					"test": {
						"name": [
							"quarkus.datasource.driver",
							"quarkus.datasource.{*}.driver"
						],
						"value": [
							"org.h2.Driver"
						]
					},
					"values": [
						{
							"name": "jdbc:h2:~/${test}",
							"docs": "Embedded test 'test' in the user home directory"
						},
						{
							"name": "jdbc:h2:/${data}/${test}",
							"docs": "Embedded 'test' in the directory /data"
						}
					]
				}
			}
		]
	}
]

If you need some explanation, please tell me. @fbricon @xorye what do you think about that?