[Cli] Include git commit on azk version

[julio-saito-linx]

this closes #605

When we display azk version we do not have what exactly git commit version. This works well for released versions but for development azk version we need to know exactly what commit that we are running.

For this we will take the current commit being executed by git.

We also will include tests on spawn_helper and perhaps further improve the output of azk version

TODO:

• [x] Create tests for Spawn Helper class
• [x] Split printOutput and spawnAsync behavior. spawnAsync should only return command executed;
• [x] Refactor all spawnAsync calls
• [x] Create GitHelper class that calls Spawn Helper class
• [x] Change azk version to return git commit id too
• [x] Create a way to get commit id from released binary azk version
• [x] git show -s --format="%ci" HEAD | tee get date from current commit

  TODO Optional

• [ ] Improve azk version to show more info [optional]

  testing

# tests
azk gulp test --grep 'Azk cli, version'
azk gulp test --grep 'should _gitspawn_VersionAsync get real current git version'
azk gulp test --grep 'Spawn Helper'
azk gulp test --grep 'Git Helper'
azk gulp test --grep 'git version:'

# real world
rm -rf /tmp/azkdemo; azk start azukiapp/azkdemo /tmp/azkdemo --git-ref benchmark -vv; (cd /tmp/azkdemo; azk stop)