Updated the Readme.md file by including some features

[Chayan-11]

1. Fixed the alignment of the title "notation-convertor" to the center position.
2. Changed the Font size and turned it bold for UI enhancement.
3. Fixed the navigable links of table of contents.
4. Added adequate space after each content to enhance readability.
5. Added "Contributors" feature at the end.
6. Finally added the "Total Lines" badge, "Stars" badge and "Forks" badge for visitors to access the stats of the project.

@adityabisoi please review the changes and merge it if you find them suitable for the Readme of the project.

The sample readme file looks as follows:

[adityabisoi]

Changes look great, but please remove the line breaks at the end of each section, as the spacing looks a bit too much.

[Chayan-11]

Changes look great, but please remove the line breaks at the end of each section, as the spacing looks a bit too much.

I've removed the line breaks. Can you review the changes if that looks fine?