chore: move `prettier`, `jest` and `eslint` configuration under `package.json`

[SauravMaheshkar]

Changes proposed by this PR can be summarised as follows :-

• Move the content from .prettierrc under the prettier key in package.json. Source(prettier docs)
• Move the content from .eslintrc.js under the eslintConfig key in package.json. Source(eslint docs)
• Move the content from .eslintignore under the eslintIgnore key in package.json. Source(eslint docs)
• Move the content from jest.config.js under the jest key in package.json. Source(jest docs)

@Gr1N Request for Review

[SauravMaheshkar]

Gentle bump @Gr1N

[Gr1N]

Thanks!