Add options to disable some tests in `scim test`

[azmeuk]

scim test could take a few additional options:

• --disable-content-type-check to allow other response content types than the ones allowed in RFC7643
• --disable-return-code-check to allow other response return codes than the ones allowed in RFC7643
• --allow-extra-parameters to tolerate extra parameters in objects
• --disable-checks CHECK_NAME ... to disable some checks to be ran