Ledgers page index.html redirect

[achowdhry-ripple]

High Level Overview of Change

Obseleted path (/index.html) now redirects to current path to ledgers page (/).

Context of Change

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (non-breaking change that only restructures code)
• Tests (You added tests for code that already exists, or your new feature included in this PR)
• Documentation Updates
• Translation Updates
• Release

TypeScript/Hooks Update

• Updated files to React Hooks
• Updated files to TypeScript

Before / After

Test Plan

[pdp2121]

Actually can you add a test similar to this one:
https://github.com/ripple/explorer/blob/staging/src/containers/App/test/App.test.jsx#L147-L162

Also, probably adding to the PR description explaining why this change is needed