Add Persian (Jalali) Calendar Support

[mojtaba13133]

Add support for Persian (Jalali) calendar alongside Gregorian in DefectDojo for date input/display.

Rationale:

Persian calendar is used in Iran, Afghanistan, Tajikistan, Uzbekistan, and Persian communities in Pakistan, India, Bahrain, UAE. This enhances accessibility for these regions.

Proposed Solution:

Implement jdatetime for Persian calendar support.
Add user/system setting to toggle calendar formats.
Update date fields (e.g., findings, engagements) to support both calendars.