Add Binance support, heavily inspired by the Coinbase one (#1317)

* feat: add Binance support (Items, Accounts, Importers, Processor, and Sync)

* refactor: deduplicate 'stablecoins' constant and push stale_rate filter to SQL

---------

Signed-off-by: Juan José Mata <juanjo.mata@gmail.com>
Co-authored-by: Juan José Mata <juanjo.mata@gmail.com>

app/models/binance_item/provided.rb

@@ -0,0 +1,9 @@
+module BinanceItem::Provided
+  extend ActiveSupport::Concern
+
+  def binance_provider
+    return nil unless credentials_configured?
+
+    Provider::Binance.new(api_key: api_key, api_secret: api_secret)
+  end
+end