Separate methods for raw SQL that leverage interpolated strings

[divega]

Currently the behavior is different if you call FromSql or ExecuteSqlCommand with an inline interpolated string (parameterization happens) or if you assign the interpolated string to a variable and then pass it to the method (the string is formatted with the arguments).

In some cases customers expect parameterization but it doesn't happen: #10080

In other cases customers expect parameterization not to happen, but it does happen: #10956

This is very confusing and hard to explain. Interpolated strings in C# were simply not designed in a way that works well with having two overloads of the same method in which one works with interpolated strings and the other one with a regular string.

I think we should separate the methods, but we can only do this in major release because it is a breaking change.

This would also imply removing the RawSqlString type.

[NickCraver]

Absolutely agree with this move. If it helps, I wrote up some more test cases on how this is confusing (and sometimes dangerous) when it first came up here: https://github.com/NickCraver/EFCoreInjectionSample/blob/master/Program.cs

[divega]

@NickCraver thanks. We are going to try to address #10080 in the shorter term with a Roslyn analyzer. I think we can probably leverage your tests as tests cases for the analyzer.

cc @anpete

[ajcvickers]

And remove or modify the analyzer?