Add customizable button labels and auto-scroll feature to WebTour

[eyupcanakman]

This pull request enhances the WebTour library by introducing customizable labels for navigation buttons and adding an autoScroll option to improve usability. These changes make the library more flexible and user-friendly.

Enhancements to Button Labels:

• Added a labels property to the WebTour class, allowing customization of button text for Next, Back, Done, and Close. Default values are provided, but users can override them. (src/index.js, README.md) [1] [2]
• Updated button rendering logic to use the new labels property instead of hardcoded text. (src/index.js)

Auto-Scrolling Feature:

• Introduced an autoScroll option in the WebTour configuration. When enabled, the library automatically scrolls to the target element during navigation. (src/index.js, README.md) [1] [2]
• Implemented autoScroll behavior in the popover and fixed positioning logic to ensure smooth scrolling to the active element. (src/index.js) [1] [2]