feat: add monthly budget field and statistics (#329)

includes/i18n/en.php

@@ -85,7 +85,11 @@ $i18n = [
     'average_monthly' => "Average Monthly Subscription Cost",
     'most_expensive'  => "Most Expensive Subscription Cost",
     'amount_due'      => "Amount due this month",
+    'percentage_budget_used' => "Percentage of budget used",
+    'budget_remaining' => "Budget Remaining",
+    'amount_over_budget' => "Amount over budget",
     'monthly_savings' => "Monthly Savings (on inactive subscriptions)",
+    'yearly_savings'  => "Yearly Savings (on inactive subscriptions)",
     'split_views'     => "Split Views",
     'category_split'  => "Category Split",
     'household_split' => "Household Split",
@@ -101,7 +105,9 @@ $i18n = [
     'upload_avatar'   => "Upload Avatar",
     'file_type_error' => "The file type supplied is not supported.",
     'user_details'    => "User Details",
-    "household"        => "Household",
+    "monthly_budget"  => "Monthly Budget",
+    "budget_info"     => "Monthly budget is used to calculate statistics",
+    "household"       => "Household",
     "save_member"     => "Save Member",
     "delete_member"   => "Delete Member",
     "cant_delete_member" => "Can't delete main member",