Spid-sp-test

- unit tests
- fixed authn requests from html file://
- added support for authn request via file:// in xml format
- added parameter --no-send-response, to deal with third party test IdP that want to handle the http I/O by their own

test pipy action

sslyze removed from strict dependencies

- fixed many tests
- added exit-zero, html dumps, json configuration file for tests and assertions, see `spid_sp_test -h`
- tested in a real CI pipeline

- fixed fake idp metadata export
- added an additional check on faulty authn requests html form

- setup dependencies
- minor changes in README