Problem: x/params is deprecated, need to migrate away from it

[adu-crypto]

👮🏻👮🏻👮🏻 !!!! REFERENCE THE PROBLEM YOUR ARE SOLVING IN THE PR TITLE AND DESCRIBE YOUR SOLUTION HERE !!!! DO NOT FORGET !!!! 👮🏻👮🏻👮🏻 close #632

According to the recent Cosmos-SDK ADR 046: Module Params , we should migrate x/cronos module away from x/params to enable stateful params changes, as well as more efficient params serialization.

• [x] store params in x/cronos store instead of subspace
• [ ] create and handle MsgUpdateParams for grpc msgServer
• [ ] support querying params of x/cronos
• [ ] write and register migration plan

PR Checklist:

• [ ] Have you read the CONTRIBUTING.md?
• [ ] Does your PR follow the C4 patch requirements?
• [ ] Have you rebased your work on top of the latest master?
• [ ] Have you checked your code compiles? (make)
• [ ] Have you included tests for any non-trivial functionality?
• [ ] Have you checked your code passes the unit tests? (make test)
• [ ] Have you checked your code formatting is correct? (go fmt)
• [ ] Have you checked your basic code style is fine? (golangci-lint run)
• [ ] If you added any dependencies, have you checked they do not contain any known vulnerabilities? (go list -json -m all | nancy sleuth)
• [ ] If your changes affect the client infrastructure, have you run the integration test?
• [ ] If your changes affect public APIs, does your PR follow the C4 evolution of public contracts?
• [ ] If your code changes public APIs, have you incremented the crate version numbers and documented your changes in the CHANGELOG.md?
• [ ] If you are contributing for the first time, please read the agreement in CONTRIBUTING.md now and add a comment to this pull request stating that your PR is in accordance with the Developer's Certificate of Origin.

Thank you for your code, it's appreciated! :)