Remove MaterialModel::InterfaceCompatibility

[tjhei]

This involves deriving MaterialModel's from MaterialModel::Interface instead of MaterialModel::InterfaceCompatibility and implementing evaluate:

• convert tests
• convert benchmarks/cookbooks
• remove class

[bangerth]

@alarshi -- can you list here the numbers of the pull requests you wrote that make this conversion? I see #1706, #1700, #1699. Did I miss any?

We like to keep track which pull requests address which issue. Ideally, pull requests list the issues they address so that github can keep track of these connections.

[gassmoeller]

Resolved in a whole bunch of pull requests by @alarshi. Thanks!

[bangerth]

Yay!