Separate Task classes in P2pMgr

[aionick]

Description

Please include a brief summary of the change that this pull request proposes. Include any relevant motivation and context. List any dependencies required for this change.

• NodeMgr class previously contained a number of nested classes all in one module. I've moved each of these classes into their own modules and have done minor refactorings for readability etc.

Fixes Issue # .

Type of change

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• Bug fix.
• New feature.
• Enhancement.
• Breaking change (a fix or feature that causes existing functionality to not work as expected).
• Requires documentation update.

Testing

Please describe the tests you used to validate this pull request. Provide any relevant details for test configurations as well as any instructions to reproduce these results.

• Ran kernel in debug mode with miners and checked against our current test cases.

Verification

Insert x into the following checkboxes to confirm (eg. [x]):

• I have self-reviewed my own code and conformed to the style guidelines of this project.
• New and existing tests pass locally with my changes.
• I have added tests for my fix or feature.
• I have made appropriate changes to the corresponding documentation.
• My code generates no new warnings.
• Any dependent changes have been made.