Added support for a special codespeed_name for a benchmark

The codespeed_name is configured as part of the run configuration in a benchmark suite, see tests/codespeed.conf.
It supports a couple of string expansions: %(cores)s, %(input_sizes)s, and %(extra_args)s.

Example:

TestSuite1:
        performance_reader: TestVMPerformance
        # location: /Users/...
        command: TestBenchMarks %(benchmark)s %(input)s %(variable)s
        input_sizes: [2, 10]
        benchmarks:
            - Bench1:
                codespeed_name: "Bench1 with fancy name %(cores)s %(input_sizes)s %(extra_args)s"
            - Bench2:
                extra_args: 6

Signed-off-by: Stefan Marr <git@stefan-marr.de>