Use a progress reporter to hint the current build status when run or debug a program

[testforstephen]

This PR includes:

• Use a consistent progress reporter to report the build status before running/debugging an application.
  By default, progress notifications are used to display status. You can switch to using status bar to hint the progress by user settings "java.silentNotification": true.

• Expose an extension API for test runner to use the same progress reporter. In addition, when third-party extensions such as test runner call the startDebugging API to start the debugger, they can add an attribute __progressId to the launchConfiguration so that the debugger can use the same progress reporter to report progress.

// The debugger will export the progressProvider instance to others for reuse.
{
  progressProvider: IProgressProvider
}

export interface IProgressReporter {
    /**
     * Returns the id of the progress reporter.
     */
    getId(): string;

    /**
     * Reports a progress message update.
     * @param message the message to update
     * @param increment use `increment` to report discrete progress. Each call with a `increment`
     *                  value will be summed up and reflected as overall progress until 100% is reached.
     *                  Note that currently only `ProgressLocation.Notification` is capable of showing
     *                  discrete progress.
     */
    report(message: string, increment?: number): void;

    /**
     * Shows the progress reporter.
     */
    show(): void;

    /**
     * Hides the progress reporter.
     * @param onlyNotifications only hide the progress reporter when it's shown as notification.
     */
    hide(onlyNotifications?: boolean): void;

    /**
     * Returns whether the progress reporter has been cancelled or completed.
     */
    isCancelled(): boolean;

    /**
     * Notifies the work is done that is either the task is completed or the user has cancelled it.
     */
    done(): void;

    /**
     * The CancellationToken to monitor if the progress reporter has been cancelled by the user.
     */
    getCancellationToken(): CancellationToken;

    /**
     * Disposes the progress reporter if the observed token has been cancelled.
     * @param token the cancellation token to observe
     */
    observe(token?: CancellationToken): void;
}

export interface IProgressProvider {
    /**
     * Creates a progress reporter.
     * @param jobName the job name
     * @param progressLocation The location at which progress should show, defaults to `ProgressLocation.Notification`.
     * @param cancellable Controls if a cancel button should show to allow the user to cancel the progress reporter,
     *                    defaults to true. Note that currently only `ProgressLocation.Notification` is supporting
     *                    to show a cancel button.
     */
    createProgressReporter(jobName: string, progressLocation?: ProgressLocation | { viewId: string }, cancellable?: boolean): IProgressReporter;

    /**
     * Returns the progress reporter with the progress id.
     * @param progressId the progress id
     */
    getProgressReporter(progressId: string): IProgressReporter | undefined;
}

[testforstephen]

A private vsix to test the progress reporter feature. https://github.com/testforstephen/vscode-test/blob/master/vscode-java-debug-0.29.1.vsix

Below is a sample to show the progress reporter such as resolving main class, compiling workspace, resolving launch configuration.

[jdneo]

I have one question: When do we need to manually call progressReporterManager.remove()?

[testforstephen]

I have one question: When do we need to manually call progressReporterManager.remove()?

Good question, you don't need call it. It's supposed to be used by progressReporter.cancel().

[testforstephen]

Here is a new private vsix https://github.com/testforstephen/vscode-test/blob/master/vscode-java-debug-0.29.2.vsix