License incoherent

[almereyda]

A watchful eye found an inconsistency in our licensing practice.

@KnowledgeGarden commented 8 hours ago at this fork's source:
The transformap.co says it is LGPL; the license posted here is GPL. Which?

We ought to choose one which also has to be compatible with the source template of this git tree.
Useful links to look at are:

• transformap.github.io/src/layouts/default.html.eco

  Line 90 in b466898

  Content licensed under <a href="https://creativecommons.org/licenses/by-nc-sa/4.0/" target="_blank">CC-BY-SA 4.0</a> | Website licensed under <a href="https://github.com/keikreutler/transformap/blob/master/LICENSE.md" target="_blank">LGPL v3.0</a>

  and
• fc06276