Add Zoom In/Out feature

[SlavaVedernikov]

Context

When presenting/discussing diagrams of certain Level of Details e.g. Context or Container, sometimes it's helpful to understand what is happening at a lower level of details in some part(s) of a particular Context diagram and sometimes there is too much details in some parts of a Container diagram.

Example 1: You've got a Context diagram with 10 Software Systems (boxes) and their interactions (lines) and you want to focus on details of only one or two Software Systems at Container level. The only way to do that at the moment is to load Container diagram for the same Scope, but that diagram may have too much details (i.e. all Containers of all Software Systems and their interactions)

Example 2: You've got a Container diagram with 5 Software System Boundaries (outlines) and 20 Containers (boxes) inside those boundaries and their interactions (lines) and you are not interested in Containers within one or two Software Boundaries, it's enough to just see Software Systems for those. There is no way to do this at the moment.

Requirements

Introduce zoom-in-structures and zoom-out-structures options for draw-diagrams command.
These options would accept one or many Structure aliases (supporting shortcuts).

The draw-diagrams would work as follows:

Example 1: zoom-in-structures option would take aliases of one or two Software Systems that you want to zoom in. For those Software Systems only draw-diagrams would draw Software System Boundaries (outlines) instead of Software Systems (boxes) and add the corresponding Containers (boxes) to those boundaries. Interactions (lines) would go to/from relevant Containers (not Software Systems)

Example 2: zoom-out-structures option would take aliases of one or two Software Systems that you want to zoom out. For those Software Systems only draw-diagrams would draw Software Systems (boxes) instead of Software System Boundaries (outlines). Interactions (lines) would go to/from relevant Software Systems (not Containers)

TODO: Add diagrams for each example for current state and with Zoom In/Out effect.