Support trusted setup configuration

[tbenr]

From polynomial commitments:

• Support trusted setup loading. We should have a trusted_setup.txt backed in for testnets\mainnet with the ability to specify via CLI for devnets. We just have to use the file content as is to initialize the kzg library by calling load_trusted_setup.

We should have the trusted setup configured in Eth2NetworkConfiguration and map the corresponding setup in each applyNetwork* methods.

We also have to load itKZG.loadTrustedSetup. BeaconChainController::initialize is a good candidate