Add automated tests to verify curl's TLS signature

Add automated testing infrastructure with tests verifying that
`curl-impersonate` has the same TLS signature as that of the
impersonated browser.

Each wrapper script (e.g. curl_chrome98) is launched to wikipedia.org
while a packet capture is running in the background. The Client Hello
is extracted from the capture, parsed and then compared to the known
browser signature.

The known signatures are stored in a YAML database.

tests/requirements.txt

@@ -0,0 +1,3 @@
+pyyaml
+pytest
+dpkt