Disable SSL check

[sortafreel]

• Allow enabling/disabling SSL certificate checks in sessions through TCPConnector.
• Add mockserver with SSL support.
• Add tests.

[Gallaecio]

In which scenarios do we need this feature?

[kmike]

I think it's a port of zytedata/zyte-autoextract#37 to this library.

[Gallaecio]

Should we consider the Zyte Smart Proxy Manager approach instead? They provide a downloadable CA certificate and installation instructions, so users can get things working without security compromises.