Implement SDL-0116 Open Menu RPC

[justingluck93]

Fixes #806

This PR is ready for review.

Risk

This PR makes minor API changes.

Testing Plan

Send a RPC request to HMI to open the menu

SDLShowAppMenu *showMenu = [[SDLShowAppMenu alloc] init];
[self.sdlManager sendRequest:showMenu withResponseHandler:^(__kindof SDLRPCRequest * _Nullable request, __kindof SDLRPCResponse * _Nullable response, NSError * _Nullable error) {
       if (error != nil) { return; }
       // Use Response if needed
    }];

SDLShowAppMenu *showMenu = [[SDLShowAppMenu alloc] init];
showMenu.menuID = //MenuID With SubCells
[self.sdlManager sendRequest:showMenu withResponseHandler:^(__kindof SDLRPCRequest * _Nullable request, __kindof SDLRPCResponse * _Nullable response, NSError * _Nullable error) {
       if (error != nil) { return; }
       // Use Response if needed
    }];

CLA

• I have signed the CLA

[joeljfischer]

I think this is the last of the formatting errors