Add initial notes on banana pi benchmark setup.

Our benchmarks require isolation from other system effects. Additionally,
we would like to have a system with 'very symmetric cores' (no hyperthreading,
no different memory connections, ....) that falls more into  the embedded
class of devices than desktop processors do. The notes describe how to setup
an banana pi m3 with a linux distri with rt preemt patch to achieve this.
3 jobs from coninuation in 3 minutes 21 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #3632
build_cmake

00:54

 
  Test
passed #3633
run_tests

00:50

 
  Sanitizer
passed #3634
run_address_sanitizer

01:36