Updated README with some changes for the Data Analyst Roadmap

[Omsongire23]

A few improvements on the README have been done in this update for better user experience of those following the Data Analyst Roadmap:

1. Refreshed Visual Elements :
   Implemented new images for Power BI and Tableau under the section of Business Intelligence Tools. Such graphics help increase more awareness and thus, help to create a sharp prominence over the business intelligence tools which allows a learner to understand even more as they train.
2. Included External Sources:

• Provided additional links to further the links in Advanced Excel and R Programming, in which the readers will be forwarded to more auxiliary materials, tutorials, and references about further learning of these areas, to further study these areas in the analysis of data.
• 3. Improved Layout & Structure:
• README formatting and structuring were smoothed out for easier and clearer readability: sections reordered and cleaned up, as well as sometimes made to flow in an easier sequence for the reader. This way, hopefully, it will be even easier for those aspiring data analysts to walk the roadmap in line.

Changes:

• Image updates for both Power BI and Tableau.
• Added external resources to learn outside of the class for Advanced Excel and R Programming
• Reformatted the README so that it's easier to read and follows better user flow

This way, the use of these materials will be very beneficial as they can clearly access them and progress effectively in their journey to becoming data analysts.