Fixed header on Daily Timesheet

To improve the usability of the Daily Timesheet, the header section is now anchored at the top of the screen and is always visible. An additional Submit button was also added to the top header section, so that users can submit a timesheet without having to scroll down to the bottom of the page. The top Submit button is always visible even when the user scrolls down or if there is data that extends beyond the right side of the visible window.