What is this PR for?

• Bug fix
• New feature
• Docs update
• Tests update
• Other

Description

From #329, a comment about tests/test_framework/mock_rpc.py was made:

In the old days, before floresta could connect with actual peers, we used a client-server wire implementation. This module mimics that server, but floresta is by default built with experimental-p2p, so if you want them to connect with something you need to start a p2p server (it can either be an actual utreexod or a mocked version like core does)

So this PR remove the files:

• tests/test_framework/mock_rpc.py;
• tests/data/rpc/{blocks, block_index, proofs}.json