Dapper.Contrib operations should accept an optional table name

[mniak]

There are scenarios where one could prefer specifiing the table name for that specific insert/update/etc.

My suggestion is to add an optional parameter that when not specified would make the methods work as they currently do.
If specified, the method then uses that table name.

I have considered to configure through SqlMapperExtensions.TableNameMapper, but it still is a problem if I need to insert the same entity in two different tables concurrently.

I'm willing to contribute

[mniak]

Please check the PR DapperLib/Dapper#1622 where I implemented this