Revise endpoints for adding/updating counterparty metadata

Please review endpoints which add/update Counterparty metadata:

"metadata":{
    "public_alias":"ALIAS_1C5520",
    "private_alias":null,
    "more_info":null,
    "URL":null,
    "image_URL":null,
    "open_corporates_URL":null,
    "corporate_location":null,
    "physical_location":null
 }

For instance we have one endpoint for adding and one for updating of field "more_info":

• POST /banks/BANK_ID/accounts/ACCOUNT_ID/VIEW_ID/other_accounts/OTHER_ACCOUNT_ID/metadata/more_info
• PUT /banks/BANK_ID/accounts/ACCOUNT_ID/VIEW_ID/other_accounts/OTHER_ACCOUNT_ID/metadata/more_info
  which use next type of JSON as input :

{  "more_info":"More info..."}

We should consider can we reduce two endpoints into one.

Inizia esaminando gli endpoint POST e PUT per il campo other_accounts metadata/more_info e confronta il relativo input JSON e comportamento con i campi metadata della controparte elencati. Il lavoro è completato quando la strategia degli endpoint è stata decisa e le operazioni di add/update hanno una forma API coerente e documentata.