Parts of Repo Should Have More Specific Exception Types

[gunnarmiller]

Several parts of the repo should be modified to use more specific exception types to make exception handling and debugging easier. Possible categories include:

1. Exceptions encountered by miners attempting to mine or validate blocks. These are likely to be used primarily in src/agents/miner.py, src/agents/trial_manager.py and src/protocols/proof_of_work_protocol.py
2. Exceptions related by issues connecting to D-Wave solvers. These are likely to be used primarily in src/protocols/hash_calculator.py and src/utilities/quantum_cubic_utils.py
3. Exceptions caused by errors in Block data structure. These should mostly be used in src/structures/block.py, though perhaps some may also be appropriate in src/agents/miner.py
4. Exceptions caused by the structures managing the blockchain reaching an invalid state. These should be used in src/structures/block_score_tree.py and src/structures/score_tree_branch.py