Add build/compile-time options for some APIs?

[garethsb]

Now that NMOS is expanding in several more directions, it would be good to demonstrate that nmos-cpp is not monolithic.

Suggestion: build/compile-time options that show the modularization possibilities...

• IS-04 and IS-05 should always be included in libnmos
  • BCP-002-01 always included (v small)
  • BCP-002-02 always included (v small)
  • probably BCP-004-01 always included
• most others should be possible to opt out at build/compile-time
  • IS-07
  • IS-08
  • IS-11 and IS-12 (when merged)
  • maybe IS-13 (when merged)?
  • maybe IS-09?
  • maybe IS-10 (when merged)?
• what about support for different media formats... can these be modularized?
  • video/raw (ST 2110-20)
  • audio/L (ST 2110-30)
  • video/smpte291 (ST 2110-40)
  • video/SMPTE2022-6 (ST 2022-8)
  • video/jxsv (ST 2110-22, BCP-006-01)
  • video/H264 (when implemented per BCP-006-02)
  • video/H265 (when implemented per BCP-006-03)
  • etc.

In an ideal world, I would expect that using explicit build/compile-time options would make little difference to the overall code size vs. using current libnmos.a static library, since linker should be clever enough to remove unused objects... However, I know that there are some objects that will currently tie everything together, e.g. nmos/json_schema.cpp and nmos/node_server.cpp.

Another possibility is just to show in nmos-cpp-node how to exclude the various optional APIs like IS-07 and IS-08.