prometheus: add server setup documentation #487

Job	Run time
Test with DPDK enabled / test	11m 52s
Test (clang++, C++20, debug) / test	7m 19s
Test (clang++, C++20, dev) / test	4m 33s
Test with C++20 modules enabled / test	11m 12s
Test (clang++, C++20, release) / test	5m 0s
Test (clang++, C++23, debug) / test	8m 9s
Test (clang++, C++23, dev) / test	5m 14s
Test (clang++, C++23, release) / test	16m 24s
Test (g++, C++20, debug) / test	10m 33s
Test (g++, C++20, release) / test	8m 41s
Test (g++, C++20, dev) / test	4m 16s
Test (g++, C++23, debug) / test	10m 58s
Test (g++, C++23, dev) / test	4m 26s
Test (g++, C++23, release) / test	10m 7s
	1h 58m 44s

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