Import Spring Data R2DBC module into Spring Data Relational #1179
Description
Going forward we want to keep JDBC and R2DBC modules within a single repository so that we can apply refactorings within a single scope as the actual technologies are just a lower-level implementation of the database connectivity layer while the core Spring Data functionality remains the same.
Both modules should achieve the same level of functionality and co-locating the code of both modules makes this much easier.