Rename create_tinylabel

[Pakillo]

For consistency, it should probably be renamed as create_tiny_label, like the other functions. Before #54

[Pakillo]

Actually some functions are "create_certificate_type" but label functions are "create_collection_label" etc. instead of "create_label_type". Probably not necessary to change at this point, but could be changed for consistency

[juliagdealedo]

You are right, all function names should be changed. However, we have encountered some problems by doing so, we have decided to change it afterwards in an other branch and after the cran check.

[Pakillo]

Which problems? Let me know if I can help.
Any function name change should ideally be done before submitting to CRAN, to avoid breaking changes once it's public there

[iramosgutierrez]

closed in commit d1ce6ce