feat: implement GetParams for precompiles

[zsystm]

Description

Closes: #270

Summary of changes

• Implemented GetParams methods for the following precompiles:
  • Staking
  • Distribution
• Skipped GetParams implementation for the Bank precompile, as we are using the precisebank keeper, which does not expose any parameters to retrieve.
• Skipped GetParams implementation for the ERC20 precompile as well, since it is a shared implementation used by multiple dynamic precompiles. Adding a global GetParams method would apply to all of them uniformly, which may not be appropriate or meaningful in every context.

Notes

• This PR depends on tests: add precompile solidity e2e tests  #253, which introduces Solidity-based E2E tests for precompiles.
• E2E test cases for GetParams will be added after tests: add precompile solidity e2e tests  #253 is merged.

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[cloudgray]

LGTM with nit!

[cloudgray]

LGTM!