Migration SQL should not be one long line of SQL

[ckoppelman]

I write view_definition SQL in my model as long multiline strings. When I run makeviewmigrations,
it just spits out the string in one long line, newlines included. It would be much easier to read if it
would generate a multiline string as I write. I'm not sure that's easy to do, but perhaps if there's a
newline in the string, it can be a clue to generate a multiline string instead of a single line. Honestly, I'd like
it even more if the multiline strings were variables that were pulled out, but I can see different opinions on that.

[BezBartek]

I will dig into it, I hope that it will be easy to change