Removed websocket++ as a dependency

[AssemblyJohn]

Describe your changes

Removed websocket++ from the cmake files and source files.

Issue ticket number and link

Closes: #387 (comment)

Checklist before requesting a review

• I have performed a self-review of my code
• I have made corresponding changes to the documentation
• If OCPP 2.0.1: I have updated the OCPP 2.0.1 status document
• I read the contribution documentation and made sure that my changes meet its requirements

[AssemblyJohn]

I'd require some ideas on the new websocket class implementation name (from file 'websocket_libwebsockets.cpp' and name 'WebsocketTlsTPM'), since we already have a file called 'websocket.cpp' & a class called 'Websocket'.

[Pietfried]

I'd require some ideas on the new websocket class implementation name (from file 'websocket_libwebsockets.cpp' and name 'WebsocketTlsTPM'), since we already have a file called 'websocket.cpp' & a class called 'Websocket'.

The filename websocket_libwebsockets is fine. The class name would then be WebsocketLibwebsockets.

[marcemmers]

There are still some websocketpp header files present that should be removed. Both in the include/common/websocket and in 3rd_party.

Also, can't we just get rid of the Websocket class itself since it is just a wrapper over WebocketLibwebsockets now that only adds a few log lines. Then we no longer have this question of naming either. Just name WebocketLibwebsockets Websocket and we are done.

[AssemblyJohn]

There are still some websocketpp header files present that should be removed. Both in the include/common/websocket and in 3rd_party.

Also, can't we just get rid of the Websocket class itself since it is just a wrapper over WebocketLibwebsockets now that only adds a few log lines. Then we no longer have this question of naming either. Just name WebocketLibwebsockets Websocket and we are done.

Removed the unused headers, thanks for pointing it out! The 3rd_party is required for some URI validation. I don't exclude in the future to write our own code to take care of that. As for Websocket/WebsocketLibwebsockets, it's better to remain like this since we might add an alternate library instead of libwebsockets. Or at least that is how it was designed in the first place.