[FEAT] Set zoom in / zoom out max values

[NathalieC]

At some point (exists in mxGraph?), a max zoom in and out levels are reached.
Possible solutions to be discussed

• Max zoom out should be reached when the diagram fit the viewport.
• Max zoom in should be one element fitting the viewport (task / event). This is very big, but this can really help visually impaired people.

Interactions with other features

Please keep in minds the following features when implementing this one

• Zoom events: [FEAT] Send events on Zoom #1488
• interaction with the zoom API [FEAT] Add API to zoom programmatically #1487: when values reached, send events only (remember throttle/debounce)

[tbouffard]

This feature may force us to deal with mxgraph minFitScale and maxFitScale to ensure we have the same constraints for zoom and fit.
See https://github.com/jgraph/mxgraph/blob/v4.2.0/javascript/src/js/view/mxGraph.js#L1571-L1585
Zoom scale constraints also exist by default for zoom triggered by pinched gestures (https://github.com/jgraph/mxgraph/blob/v4.2.2/javascript/src/js/handler/mxPanningHandler.js#L434)

[tbouffard]

The lib must manage something on its side as the integration has no way to ensure this when the user is doing zoom with the mouse wheel.
This feature was temporarily available during development of #791. Reverted with 814fda6 (#791) and 185acd9 (#791)