[Feature] Store all tools and categories in global objects

[negarjf]

Title

Store all tools and categories in global objects

Related to Issue #114

Number of files/folder added

1 folders and 2 files

- assets [folder]
-- config [folder]
--- categories.js
--- tools.js

Changes made

• Store all categories in categories.js in a global object named: UTILITY_CATEGORIES. Each category has a title and an icon
• Store all tools in tools.js in a global object named: UTILITY_TOOLS . Tools are grouped by category. Each tool object has a title, a description, and a URL.
• Both js files have been added to the index.html
• Update README and CONTRIBUTING files

I have:

• Read contributing.md
• Followed all the guidelines
• Linked my tool to the index.html file
• updated readme.md