[EVM] Precompile admin toggles

[gztensor]

Create admin pallet methods (callable by sudo only) that will allow to toggle precompiles on and off. In order to avoid admin pallet pollution, implement it as a single sudo_toggle_evm_precompile extrinsic that accepts two parameters:

1. Precompile ID (emun)
2. Boolean to enable / disable

Precompile ID should be the enum with following options:

• BalanceTransfer
• Staking
• Subnets
• Neurons

If a precompile is disabled, any call to the precompile should fail with following error:

            return Err(PrecompileFailure::Error {
                exit_status: ExitError::Other("Precompile is disabled".into()),
            });

[keithtensor]

This is done in #1131.