add meson usage guide

[UnixY2K]

description

Draft for meson docs in the project readme an usage Guide, needs some cleanup and should come after #394 #391 so the examples and project work out of the box in OSX 11+ under meson

changes

• README.md
  • add build and installation guide for meson
• examples/
  • add a meson.build into examples directory (optional but preferred as the examples may grow in the future)
  • add example 1 meson.build > needs cleanup once OSX is building
  • add example 2 meson.build > needs cleanup once OSX is building
  • add an sqlitecpp.wrap example file (under the subprojects root folder of the project)
• meson.build > needs to change the build of example to subdir

note: once meson support is mature enough it should be possible to add it on wrapdb and add a proper guide in the future

[UnixY2K]

I think there is nothing else left for this PR as the CI should come on another PR.

perhaps as the documentation and example grows they should be moved to a wiki when the readme gets too big.

[UnixY2K]

will mark it as ready for review, but if there is someone else that want something changed or noticed something missing/wrong feel free to comment it.

[SRombauts]

Thanks a lot, once more, for all your work arround messon and the lib in general!