Improve readability for .gitpod.yml task log output

[axonasif]

Is your feature request related to a problem? Please describe

Tasks execution feels quite verbose and could confuse a new user to understand what's actually happening due to the duplicated printouts.

This is specially more important when you're creating templates and want to provide the user with some instructions in the terminal. For example, in template-flutter, as a workaround we're having to clear the whole terminal.

Describe the behaviour you'd like

Something like this:

This is done by executing bash with the task in cmdline instead of sending to the pty that causes the duplicate printouts. For long tasks source command is used in cmdline from a pipe.

Describe alternatives you've considered

Additional context

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.