A1 and disable infinite grid

[luke-quadratic]

Infinite grid presents design challenges across the app and is unfamiliar.

The following is roughly the desired spec:

You could have custom combinations like:
An infinite sheet
0 -> infinity
10 x 10
Whatever size you want - can go as small or as big as desired

Where the default is:
X: [0-> infinity)
Y: [0 -> infinity)

(Prompted by @davidkircos via sufficient response from users that this is confusing behavior and should be optional)

Additionally, we are moving to A1 notation as part of the same scope of work, design in Quadratic

[davidfig]

We should discuss. If we remove it completely, it simplifies a bunch of technical problems. Not sure why we would support it if it's off by default.

[davidkircos]

@davidfig the only reason I can think of is for backwards compatibility with existing files. But we could also migrate them in the file version upgrade.

It could be the right decision to have finite files only. We should discuss live.