Update javascript-styleguide packages to be compatible with eslint v9

[gokulprasanth-ni]

Justification

• Upgrade to ESLint 9 #155

Resolves #155

Implementation

• Remove all the legacy config files and replace them with flat config files.
• Update the configurations to use flat config format
• Update the dependencies version that support eslint v9.
• Update the READMe doc related to this eslint v9 change.

Testing

• Packed and applied the updated style guide in our client app - linting passed successfully.

[rajsite]

@gokulprasanth-ni please note some of the changes in recent updates we'd want to see in other PRs downstream when updating reops to use the config such as:

• Using the defineConfig pattern in all eslint.config.js files
• Using tsConfigRootDir: import.meta.dirname, instead of doing path parsing
• Avoiding unnecessary array spreads on configuration, i.e. just need extends: typescriptConfig,, etc
• For non-trivial transforms to "type": "module" those changes should be staged separately (a pr to transition to module first and then eslint chnages) or eslint should use commonjs style configuration and file tech debt to transition the package to module