Moved fuzz dir to test/fuzz

Extended contributing document to testing and licensing

test/fuzz/README.md

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+# Fuzzing with AFL
+
+Clixon can be fuzzed with [american fuzzy lop](https://github.com/google/AFL/releases) but not without pain.
+
+Some issues are as follows:
+- Static linking. Fuzzing requires static linking. You can statically link clixon using: `LINKAGE=static ./configure` but that does not work with Clixon plugins (at least yet). Therefore fuzzing has been made with no plugins using the hello example only.
+- Multiple processes. Only the backend can run stand-alone, cli/netconf/restconf requires a backend. When you fuzz eg clixon_cli, the backend must be running and it will be slow due to IPC. Possibly one could link them together and run as a monolith by making a threaded image.
+
+Restconf also has the extra problem of running TLS sockets.
+
+## Prereqs
+
+See [AFL docs](https://afl-1.readthedocs.io/en/latest) for installing afl.
+On ubuntu this may be enough:
+```
+  sudo apt install afl
+```
+Or get source: `https://github.com/google/AFL`
+
+You may have to change cpu frequency:
+```
+  cd /sys/devices/system/cpu
+  echo performance | tee cpu?/cpufreq/scaling_governor
+```
+
+And possibly change core behaviour:
+```
+  echo core >/proc/sys/kernel/core_pattern
+```
+
+### backend/restconf
+
+Backend and restconf requires the preeny package to change sockets to stdio. 
+
+Preeny has a "desocketizing" module necessary to map stdio to the internal sockets that the backend uses. Install preeny example:
+```
+  sudo apt install libini-config-dev # debian/ubuntu
+  sudo apt install libseccomp-dev # debian/ubuntu
+  git clone https://github.com/zardus/preeny.git
+  cd preeny
+  make
+  sudo cp x86_64-linux-gnu/desock.so /usr/local/lib/ # install
+```
+