Add methods related to node options to NodeBuilder

[Soya-Onishi]

Closes #142

This PR add node options related to rcl_node_options_t.
However, methods related to allocator options (e.g. NodeBuilder::allocators.allocate) are not implemented because there are no way to return allocated heap pointer as far as I know.

[nnmm]

Thanks! I'll add more comments later.

[nnmm]

@Soya-Onishi Great work! Could you also add Drop instances for rcl_node_options_t and rcl_arguments_t that call their fini functions?

[nnmm]

I tested it out and got an error about rcl_arguments_fini being called twice (which makes sense, because rcl_node_options_fini also calls rcl_arguments_fini). So we should probably remove the Drop impl for rcl_arguments_t again, that would be easiest.

Apart from that, I only have one other comment (about enable_rosout), then it's ready to merge!

[nnmm]

@Soya-Onishi Could you adjust the CString operations to match #190, which was merged in the meantime?

[nnmm]

@Soya-Onishi I have another PR that conflicts with this one, #193. If you plan to make the couple of remaining fixes this week, I can wait with my PR until we merge this one, so you don't have extra work.

[esteve]

@Soya-Onishi thanks for all the hard work and for the patience iterating with us! 🙂

[nnmm]

Wonderful! Thanks @Soya-Onishi!

[Soya-Onishi]

@nnmm @esteve
Thanks for your many advices and picks!

[nnmm]

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