Fix missing options related to 'Tasks'

[alvsan09]

What it does

Fixes: #12455

The following user options were added:

When selecting Terminal-> Run Task...

• Display a + Configure Task entry when no tasks are configured (above contributed items)
• Add Show All Tasks... entry at the bottom of the list of contributed tasks.
• Improve ordering of entries (in a multiroot, sort by root then label)
• Add Go back ↩ option from second level picks.

When selecting Terminal-> Configure Tasks...

• Add missing plugin provided entries with the scope workspace
• Order by scope, then by task label.

How to test

Prerequisites:

1. Install Gulp CLI (Used by the Gulp builtin extension)

npm install gulp-cli -g

2. Install Jake CLI (Optionally, Used by the Jake builtin extension)

npm install -g jake

3. Activate Auto Detect preference for Gulp to on
   From the:
   Command palette -> type 'open user settings' -> click and then -> Navigate to (Extensions -> Gulp) and change 'Auto Detect' to 'on'

4. Activate Auto Detect preference for Jake to on
   From the:
   Command palette -> type 'open user settings' -> click and then -> Navigate to (Extensions -> Jake) and change 'Auto Detect' to 'on'

5. Use a clone of 'vscode' as the project to test theia with

gh repo clone microsoft/vscode

• edit .vscode/settings.json to delete the line:
  "gulp.autoDetect": "off"
• edit .vscode/tasks.json to remove the only "gulp" task
  this to prevent early activation of gulp.
• Copy a valid Jakefile.js under the root folder.
  Example test content:

desc('Default Task');
task('default', function () {
 console.log('Hello, Jake!');
});

desc('Test Task');
task('test', function () {
  console.log('This is a test task.');
});

Steps to test:

1. Testing options for Terminal-> Run Task... , + Configure task

• Using theia, open a project folder which does not have a tasks.json file
  and has a Jakefile.js.

• Open the Terminal-> Run Task... option, verity the option + Configure Task is present

• When selecting the option above, provided jake tasks shall be available

• Select a provided jake task and verify it populates the tasks.json file with it.

2. Testing options for Terminal -> Run Task..., Show All Tasks...
   Using the same project as in the previous test

• Select the option Terminal -> Run Task..., Show All Tasks...
• Validate that the plugin provided jake tasks are available (alphabetically ordered)
• Selecting an entry shall populate the configuration in the tasks.json file.

3. Testing the Terminal-> Run Task..., select type gulp, Go back ↩

• Validate that the gulp tasks are listed and alphabetically ordered
• Validate that the last entry of the list is for the option Go back ↩ and that it works to go
  back to display the previous level.

4. Repeat the steps 2 and 3 above using a multi-root workspace e.g. having theia and vscode

5. Test Terminal-> Configure Tasks...

• Using a single root workspace e.g. vscode, select the option Terminal-> Configure Tasks...
• Validate that the plugin provided configurations are available e.g. jake, gulp, npm
• Validate that the entries are sorted by scope and then by label

6. Repeat the previous step but with a multi-root project e.g. theia and vscode

See test example video (Run Task):
https://github.com/eclipse-theia/theia/assets/76971376/bab18c32-4557-4d8f-ae0b-36fe987bbb6f

See test example video (Configure Tasks...)
https://github.com/eclipse-theia/theia/assets/76971376/d1340c58-b7c2-4618-a7f7-1bf8ca1fbec7

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[alvsan09]

Last change was a re-base to latest master and addressing an offline comment from @vince-fugnitto i.e.

theia/packages/task/src/browser/quick-open-task.ts

Line 103 in e71716e

label: `$(plus) ${CONFIGURE_A_TASK}`,

[vince-fugnitto]

LGTM 👍