Allow to override SSL certificate checking

[szmurlor]

Added option to prevent SSL certificate checking. It is required to allow to accept self signed cerificates commonly used for development environments.

Solves the following error:

requests.exceptions.SSLError: HTTPSConnectionPool(host='apps.ut.edu.pl', port=443): Max retries exceeded with url: /services/users?user_id=2 (Caused by SSLError(SSLCertVerificationError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: self signed certificate in certificate chain (_ssl.c:997)')))