Txs improvements

[selankon]

• On the transaction list, show the subtype (if different from TX_UNKNOWN) instead of the type. So "Create Account" instead of "setAccount". feature: return tx subtype on tx summary vocdoni-node#1358
• Show the subtype also on the Tx details page
• Register SIK contains processId
• Make the "not found" error similar to the one in lists, where we notify the user that it may have been pruned

[selankon]

On the transaction list, show the subtype (if different from TX_UNKNOWN) instead of the type. So "Create Account" instead of "setAccount".

At the moment this is not possible because on the txList the tx summary returned by the API doesn't contain the subtype

[selankon]

PR #125 implements TX subtypes