[TIMOB-8630] iOS: Refine and document Obj-C, Obj-C++ engineering patterns/design

iOS currently has some existing [common engineering practices](https://wiki.appcelerator.org/display/pe/Coding+Standards) and ["best practices"](https://wiki.appcelerator.org/display/pe/iOS+best+practices). While these don't need to be strictly enforced, we should evaluate the existing documents for: * Completeness * Correctness * Sensibility * Langage-specific engineering questions (i.e. "pure virtual" in Obj-C, subclass vs. protocol, protocol/subclass vs. delegate, "private" method naming, etc.) In addition this ticket should be collaborative with TIMOB-8241 to begin to establish any cross-language engineering concerns about class naming, data separation, design, etc. (especially since C and C++ standards will affect both projects).