"cider-eval-buffer" cannot be configured to *not* send evaluation result to echo area

## Expected behavior
Cider should allow to configure where to send the result of the last expression to, if a buffer/file gets evaluated
## Actual behavior
Cider always sends the evaluation result of the last expression in a filer/buffer on "cider-load-file" to the echo area of Emacs.
In case this expression is large, emacs will crash/being unresponsive immediately.
## Steps to reproduce the problem
1. Create a empty clj file
2. Add a last expression into the file which produces a complex, deep, map
3. evaluate the buffer with "cider-eval-buffer"
4. Cider will send the result of 2) to the echo area and crash

### CIDER version information
latest