Setup new workflow for copyright consents maintenance

[Jan Blechta]

It seems it is agreed that hard prints are not needed, scans are ok.

1. Setup storage for scans. Push the old ones which are in hold by Johannes.
2. Document in the governance document where and how to submit them. Solved by pull request #6.
3. Update outdated form templates at https://fenicsproject.org/pub/copyright/forms/ from the source at https://bitbucket.org/fenics-project/governance/src/master/copyright-consent-forms/.

[Jan Blechta]

Subtask 3. remaining.