Decide on copyright statement

[jenniferward]

It would be helpful to our audience if we provided a clear copyright statement on the guidelines website. It would be good to allow terminology to be reused because I think in some languages we will be providing professional translations of MARC and specialized library terms for the first time.

We would have to run it past the current translators as well so they know what is happening with their work.

This probably has commonalities with the PAE license discussion: rism-digital/pae-code-spec#31