setup good naming conventions for the refactor

[AdrienLeGuillou]

Initial names lack consistency.

• parameters / params: input given to the model, what we want to calibrate
• proposal: a set of parameters to feed to the model
• outcomes: outputs of the model. Values we use for checking the parameters
• targets: the values of the outcomes we try to reach
• model: a function that takes in proposals and spits out outcomes

default_proposal -> default_parameters
waves? jobs?

make_next_proposal -> proposer?
get_results -> tester? checker?

Once that is defined, cleanup code and check