Add hidden options test + unhide mistakely hidden options

[zilm13]

Description

We constantly add new features to the Teku. Some features are designed for testing only, another spend some time in beta-testing until they are uncovered. We usually mark experimental features with --X and remove X if the option goes public. Not all options become public but some are. The issue is that sometimes we forgot to remove hidden = true in option setup when removing X. Current master branch contains several places with such options: https://github.com/ConsenSys/teku/blob/b51c0337ba645507991e559433c29d26dbecdd17/teku/src/main/java/tech/pegasys/teku/cli/options/BeaconNodeDataOptions.java#L87-L94 https://github.com/ConsenSys/teku/blob/c48028ce324e9dc29050f0a9990669c260b4a1be/teku/src/main/java/tech/pegasys/teku/cli/options/Eth2NetworkOptions.java#L47-L53 https://github.com/ConsenSys/teku/blob/07d78b002f67f91aa442aa87a85e043796b85436/teku/src/main/java/tech/pegasys/teku/cli/options/ExecutionLayerOptions.java#L116-L123 https://github.com/ConsenSys/teku/blob/1b02c47cb9302bea96104396dd7b619a210f2f0f/teku/src/main/java/tech/pegasys/teku/cli/options/ValidatorClientOptions.java#L130-L135 We need to unhide these options, so the help will be visible and create test to avoid such mistakes in the future. Test should check if every option with --[not X] is unhidden unless we could imaging the real use cases when non-X option should be hidden.