feat: Employee reminders (#25735) (#27115)

* feat: Add reminders section to HR Settings

* refactor: Extract generic function for getting Employees

* feat: Employee Work Anniversary Reminder

* feat: Daily Holiday Reminder

* fix: Unnecessary params and replace [] with .get()

* test: Daily Holiday Reminders

* test: is_holiday basic tests

* refactor: Move employee reminders code to separate module

* feat: Add advance reminder to HR settings

* feat: Advance Holiday Reminders

* refactor: get_holidays_for_employee

* feat: Email holiday reminders in advance + tests

* fix: Remove unused import

* refactor: HR Setting Reminder Section

* refactor: Remove Daily Holiday Reminders feat

* feat: Reminder miss warning

* fix: Failing test and function name change

* chore: Add patch for field rename

* chore: Rename frequency label

* fix: Failing patch test

* fix: sider and removed description of fields

* fix: email alignment

Co-authored-by: pateljannat <pateljannat2308@gmail.com>
Co-authored-by: Jannat Patel <31363128+pateljannat@users.noreply.github.com>
(cherry picked from commit 24b2a315818d08ad4cb03347ccf5297df916a5ac)

Co-authored-by: Mohammad Hussain Nagaria <34810212+NagariaHussain@users.noreply.github.com>
Co-authored-by: Jannat Patel <31363128+pateljannat@users.noreply.github.com>
diff --git a/erpnext/templates/emails/holiday_reminder.html b/erpnext/templates/emails/holiday_reminder.html
new file mode 100644
index 0000000..e38d27b
--- /dev/null
+++ b/erpnext/templates/emails/holiday_reminder.html
@@ -0,0 +1,16 @@
+<div>
+    <span>{{ reminder_text }}</span>
+    <p class="text-muted">{{ message }}</p>
+</div>
+
+{% if advance_holiday_reminder %}
+    {% if holidays | len > 0 %}
+    <ol>
+        {% for holiday in holidays %}
+            <li>{{ frappe.format(holiday.holiday_date, 'Date') }} - {{ holiday.description }}</li>
+        {% endfor %}
+    </ol>
+    {% else %}
+    <p>You don't have no upcoming holidays this {{ frequency }}.</p>
+    {% endif %}
+{% endif %}