Full rewrite of the assembly routines leveraging OO features of F2008.

• New data structures for generalized AT models, driving forces, unilateral contact laws. These require a "modern fortran" (tested with 9.0 and 10.2 under linux and macOS)
• Plasticity is temporarily broken.
• No user-facing changes, beside the incorporation of new generalized AT models.
• Updated docker containers.

0.1.0

First release required to get a DOI through Zenodo