add doc for local validation

lib/block/validation/local/block_signature.ex

lib/block/validation/local/block_time.ex

lib/block/validation/local/check_previous_issuer.ex

lib/block/validation/local/check_unit_base.ex

lib/block/validation/local/identity_signaure.ex

lib/block/validation/local/inner_hash.ex

lib/block/validation/local/membership_sig.ex

lib/block/validation/local/nonce.ex

lib/block/validation/local/parameters.ex

lib/block/validation/local/previous_hash.ex

lib/block/validation/local/proof_of_work.ex

lib/block/validation/local/transaction/transaction_count.ex

...ion/local/transaction/transaction_index_inf_nb_issuers.ex

lib/block/validation/local/transaction/transaction_input.ex

...lidation/local/transaction/transaction_number_of_lines.ex

...block/validation/local/transaction/transaction_version.ex

lib/block/validation/local/transaction/tx_sig_ordered.ex

lib/block/validation/local/universal_dividend.ex

lib/block/validation/local/version.ex