Add the ability to "rollup" values in a time series (#554)

* Clean up time series models

* Add value group rollup class for summarizing hierarchical data

* Integrate new classes

* Update UI to use new patterns

* Update D3 charts to expect new data format

* Clean up account model

* More cleanup

* Money improvements

* Use new money fields

* Remove invalid fixture data to avoid orphaned accountables

* Update time series to work better with collections

* Fix tests and UI bugs

app/models/valuation.rb

@@ -8,11 +8,8 @@ class Valuation < ApplicationRecord
 
   scope :in_period, ->(period) { period.date_range.nil? ? all : where(date: period.date_range) }
 
-  def self.to_series(account, period = Period.all)
-    MoneySeries.new(
-      in_period(period).order(:date),
-      { trend_type: account.classification, amount_accessor: :value }
-    )
+  def self.to_series
+    TimeSeries.from_collection all, :value_money
   end
 
   private