refactor: Structure global validators better

[yinyiqian1]

refactor: #1170 Structure global validators better

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 35.18519% with 35 lines in your changes missing coverage. Please review.

Project coverage is 67.86%. Comparing base (b2eacf9) to head (8e6fd49).

Files	Patch %	Lines
src/rpc/handlers/LedgerEntry.hpp	35.71%	4 Missing and 5 partials :warning:
src/rpc/handlers/BookOffers.hpp	44.44%	0 Missing and 5 partials :warning:
src/rpc/handlers/GetAggregatePrice.hpp	40.00%	0 Missing and 3 partials :warning:
src/rpc/handlers/AccountChannels.hpp	0.00%	2 Missing :warning:
src/rpc/handlers/AccountLines.hpp	50.00%	0 Missing and 2 partials :warning:
src/rpc/handlers/DepositAuthorized.hpp	0.00%	2 Missing :warning:
src/rpc/handlers/AccountCurrencies.hpp	0.00%	1 Missing :warning:
src/rpc/handlers/AccountNFTs.hpp	0.00%	1 Missing :warning:
src/rpc/handlers/AccountObjects.hpp	0.00%	1 Missing :warning:
src/rpc/handlers/AccountOffers.hpp	0.00%	1 Missing :warning:
... and 8 more

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #1484 +/- ## =========================================== + Coverage 67.81% 67.86% +0.05% =========================================== Files 233 233 Lines 9423 9438 +15 Branches 5256 5256 =========================================== + Hits 6390 6405 +15 Misses 1654 1654 Partials 1379 1379 ```

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