Clarify backend data pipeline naming concepts (importers, processors, materializers, calculators, and syncers) (#2255)

* Rename MarketDataSyncer to MarketDataImporter

* Materializers

* Importers

* More reference replacements

app/models/exchange_rate/importer.rb

@@ -1,4 +1,4 @@
-class ExchangeRate::Syncer
+class ExchangeRate::Importer
   MissingExchangeRateError = Class.new(StandardError)
   MissingStartRateError = Class.new(StandardError)
 
@@ -12,7 +12,7 @@ class ExchangeRate::Syncer
   end
 
   # Constructs a daily series of rates for the given currency pair for date range
-  def sync_provider_rates
+  def import_provider_rates
     if !clear_cache && all_rates_exist?
       Rails.logger.info("No new rates to sync for #{from} to #{to} between #{start_date} and #{end_date}, skipping")
       return

app/models/exchange_rate/provided.rb

@@ -28,20 +28,20 @@ module ExchangeRate::Provided
     end
 
     # @return [Integer] The number of exchange rates synced
-    def sync_provider_rates(from:, to:, start_date:, end_date:, clear_cache: false)
+    def import_provider_rates(from:, to:, start_date:, end_date:, clear_cache: false)
       unless provider.present?
-        Rails.logger.warn("No provider configured for ExchangeRate.sync_provider_rates")
+        Rails.logger.warn("No provider configured for ExchangeRate.import_provider_rates")
         return 0
       end
 
-      ExchangeRate::Syncer.new(
+      ExchangeRate::Importer.new(
         exchange_rate_provider: provider,
         from: from,
         to: to,
         start_date: start_date,
         end_date: end_date,
         clear_cache: clear_cache
-      ).sync_provider_rates
+      ).import_provider_rates
     end
   end
 end