Investigate the scenario of merging two protocols

[fjarri]

Two variants here:

• executing two protocols simultaneously,
• chaining two protocols one after the other.

How much boilerplate is required to do that? What tools can we provide for the users to make it easier?

[fjarri]

I just realized that due to the more dynamic nature of our protocols we may be able to get away with defining just one struct and make it handle multiple rounds. Same goes for malicious behavior tests by the way - no need to override each round separately.

[fjarri]

Chaining will be implemented in #60, merging specifically is more defined now and is tracked by #61. This can be closed.