Use byte indexes instead of lines and columns

[dsherret]

I think lines and columns is an LSP & display concern and we should remove it from deno_graph. I think deno_graph should just return byte indexes or at least have both. It would also be good to standardize any unit types with deno_ast (so probably just use swc's Span for ranges... or maybe we could make our own type that uses usize and easily converts to an swc span)

discussion_r767983595

[kitsonk]

Including the byte pos as well makes sense, but the serialization should be line and col, as it is often a situation where the consumer of the serialization doesn't want to access the source (especially in JS) and allows the conumer of a serialization to be able to display a line and col reference without going through the bytes of the original source (especially things like doc websites which only want to "link" to the source without accessing it).