Feature description

Often, when you are creating new workflows, you want to:

• copy-paste some code from other flows in the same namespace
• lookup inputs when adding a Subflow task or a flow trigger

Being able to open other flows in new Editor tabs makes those use cases much easier to handle.

TODOs

• figure out with @Nico-Kestra a new icon for a "Flow" that can be used to distinguish the main flow from other flows -- see the image below
• figure out a way to pin a "flows" directory at the top that allows viewing workflow code from other flows in that namespace and child namespaces — those flows might use the naming convention namespace_id.flow_id.yml

Requirements

1. Those flows can be opened within the same browser window (in the other Editor tabs)
2. Those flows should be editable — even though you are on a specific Flow's page, the user should be able to make some adjustments for other flows