[EPIC] New fee model architecture

[vzotova]

Type of PR:

• [ ] Bugfix
• [X] Feature
• [ ] Documentation
• [ ] Other

Required reviews:

• [ ] 1
• [ ] 2
• [X] 3

What this does: Changes fee model, now it's separate contract that must be approved in coordinator. Implements subscription for BqETH

Issues fixed/closed:

• Fixes #264
• Fixes #262

PRs:

• [x] #255
• [x] #265
• [x] #272
• [x] #273
• [x] #277
• [x] #279
• [x] #280
• [x] #283
• [x] #286
• [x] #293
• [x] #294
• [x] #295
• [x] #296
• [x] #297
• [x] #298
• [x] #299

Why it's needed:

Explain how this PR fits in the greater context of the NuCypher Network. E.g., if this PR address a nucypher/productdev issue, let reviewers know!

Notes for reviewers: This PR is ready for tests and integration with nucypher repo, ManagedAllowList needs touch up in some of following PRs

[derekpierre]

Just rebased this EPIC. Given the size of this PR - we should try to merge this soon. That being said, we should not merge it until v7.4.0 is released since merging it will cause nucypher/nucypher acceptance tests to fail because of contract changes. PR https://github.com/nucypher/nucypher/pull/3535 should remedy those issues moving forward, in the v7.5.x branch, once this PR is merged into main.