Adding pannable and zoomable canvas component

[Lindsay89]

Description

Adding a new Canvas component to make possible to pan and zoom the diagrams into it.

[9renpoto]

@antonioru hi, what can I do to help? :)

[jcamposv]

@Lindsay89 First thank you for these updates, and do you know when it will merge? thanks

[BenjaminArmijo3]

when this will be merged into master?

[devinhalladay]

@antonioru @Lindsay89 @9renpoto hi, i hope you're doing well :) do any of you happen to have an update on what it will take to get this merged? i'd be happy to contribute if i can help push it forward somehow

[hanuor]

Hey everyone. Thanks @Lindsay89 for this pull request. Just noticed an issue.
The connecting lines disappear when :

1. the canvas is zoomed out and zoomed in and then the user switches to a new tab and then comes back again to the canvas.
2. while zooming out or zooming in, if the user moves away from that div (which contains the canvas) and starts scrolling down.

Tested it for the above two use cases but there might be more. Let me know if in case you need any clarifications, please!