Instrument octopus to use likwid for performance measurement

Description

Use the marker API of likwid to enable measurements of hardware counters in octopus (e.g. FLOPS, memory bandwidth). The regions used are the same as for the internal profiling. It has to be enabled by using a certain configure switch (--with-likwid-prefix=DIR). At runtime, use likwid-mpirun -np xx -g MEM_DP -m ./octopus for e.g. measuring the operational intensity. For more information, see also https://github.com/RRZE-HPC/likwid/wiki.

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Instrument octopus to use likwid for performance measurement

Checklist

• I have checked that my code follows the Octopus coding standards