[svg] Add jest for testing framework and revised three icons into its own dir

[nebula-aac]

Added

• jest framework, react testing library
• revised bus, circle, and application into its own directory

Notes for Reviewers
This PR refers to #33 and and a continuing effort for #12

Three icons have been modified to be in its own directory.

• Application
• Bus
• Circle

Application has three icons, one outlined, one filled with default color, and one with keppel colors.

Added constants instead of hardcoding them.

Bus only has one filled icon with one default color

Circle has partial outlined and filled, but outlined is not fully outlined..

Added another script for coverage using jest

Created __testing__ directory to house the test files

Signed commits

• Yes, I signed my commits.

[aabidsofi19]

looks great. i will take the issue of creating a universal test for all icons