Postgres compatible mode for `dolt diff -r sql` and `dolt patch`

[timsehn]

dolt diff --sql may be used to build simple patches for databases that are no MySQL. Backticks are not universally supported as part of standard SQL. For instance PostgreSQL pukes on them. We should use them only when necessary.

[timsehn]

I think this issue is subsumed by the existence of Doltgres. I'm not sure we will ever generate other SQL dialects in Dolt.