Added static type checker tool: Flow

[aalman3]

Added two files:
flow_test.babelrc
.flowconfig

Code Used to add Flow:
npm install --save-dev @babel/core @babel/cli @babel/preset-flow babel-plugin-syntax-hermes-parser --installing flow
npm install --save-dev flow-bin --Adding a devDependency on the flow-bin npm package
npm run flow init --running Flow for the first time

"flow": "flow" --Add a "flow" script to package.json

How to run Flow:
npm run flow --used to run Flow checker

Output of Flow Checker:

[coveralls]

Pull Request Test Coverage Report for Build 11497635070

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 82.367%

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Totals
Change from base Build 11496083902:	0.0%
Covered Lines:	22368
Relevant Lines:	25711

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💛 - Coveralls

[rkensouh]

Can you please add more details to the PR?

[aalman3]

Added More info about Flow Static Tool