Feature - Add support for a fiscal year period defined in user settings.

* Add "This fiscal year", "Last fiscal year" as date range options in Transaction Details to filter transactions to those periods
* Add fiscal year ranges to Statistics & Trend Analysis
* Add "fiscal year start date" to user profile settings, allowing the user to select any date of the calendar year as the start of the fiscal year
* Add "fiscal year format" to user profile settings, allowing the user to specify how financial year date labels should appear

Implementation notes:
* The default fiscal year start is January 1 and the default fiscal year display format is "FY 2025"
* Fiscal year start date (month number & day number) are stored together in db as a uint16, high byte & low byte respectively
* February 29 is disallowed as a fiscal year start date, since it is never used as a convention in any country
* Jest is added to the project as a dev dependency, for unit tests in frontend

Signed-off-by: Sebastian Reategui <seb.reategui@gmail.com>

src/locales/en.json

@@ -19,6 +19,7 @@
     "default": {
         "currency": "USD",
         "firstDayOfWeek": "Sunday",
+        "fiscalYearFormat": "EndYYYY",
         "longDateFormat": "MMDDYYYY",
         "shortDateFormat": "MMDDYYYY",
         "longTimeFormat": "HHMMSSA",
@@ -85,6 +86,13 @@
             "q3": "{year}Q3",
             "q4": "{year}Q4"
         },
+        "fiscalYear": {
+            "StartYYYY_EndYYYY": "FY {StartYYYY}-{EndYYYY}",
+            "StartYYYY_EndYY": "FY {StartYYYY}-{EndYY}",
+            "StartYY_EndYY": "FY {StartYY}-{EndYY}",
+            "EndYYYY": "FY {EndYYYY}",
+            "EndYY": "FY {EndYY}"
+        },
         "misc": {
             "multiTextJoinSeparator": ", ",
             "hoursBehindDefaultTimezone": "{hours} hour(s) behind default timezone",
@@ -1196,6 +1204,7 @@
         "oldPassword": "Current Password",
         "defaultCurrency": "Default Currency",
         "firstDayOfWeek": "First Day of Week",
+        "fiscalYearStart": "Fiscal Year Start Date",
         "transactionEditScope": "Editable Transaction Range",
         "name": "Name",
         "category": "Category",
@@ -1366,6 +1375,8 @@
     "Last month": "Last month",
     "This year": "This year",
     "Last year": "Last year",
+    "This fiscal year": "This fiscal year",
+    "Last fiscal year": "Last fiscal year",
     "Recent 12 months": "Recent 12 months",
     "Recent 24 months": "Recent 24 months",
     "Recent 36 months": "Recent 36 months",
@@ -1447,10 +1458,12 @@
     "Default Currency": "Default Currency",
     "Default Account": "Default Account",
     "First Day of Week": "First Day of Week",
+    "Fiscal Year Start Date": "Fiscal Year Start Date",
     "Long Date Format": "Long Date Format",
     "Short Date Format": "Short Date Format",
     "Long Time Format": "Long Time Format",
     "Short Time Format": "Short Time Format",
+    "Fiscal Year Format": "Fiscal Year Format",
     "Decimal Separator": "Decimal Separator",
     "Digit Grouping Symbol": "Digit Grouping Symbol",
     "Digit Grouping": "Digit Grouping",
@@ -1807,6 +1820,7 @@
     "Aggregate by Month": "Aggregate by Month",
     "Aggregate by Quarter": "Aggregate by Quarter",
     "Aggregate by Year": "Aggregate by Year",
+    "Aggregate by Fiscal Year": "Aggregate by Fiscal Year",
     "Filter Accounts": "Filter Accounts",
     "Filter Transaction Categories": "Filter Transaction Categories",
     "Filter Transaction Tags": "Filter Transaction Tags",