feat: allow customizing localization path of each locale

[Josh-Cena]

Pre-flight checklist

• I have read the Contributing Guidelines on pull requests.
• If this is a code change: I have written unit tests and/or added dogfooding pages to fully verify the new behavior.
• If this is a new API or substantial change: the PR has an accompanying issue (closes #0000) and the maintainers have approved on my working plan.

Motivation

Continuation of #7386. Not sure how to test this, though...

Test Plan

Test links

Deploy preview: https://deploy-preview-_____--docusaurus-2.netlify.app/

Related issues/PRs

[github-actions]

Size Change: +66 B (0%)

Total Size: 801 kB

Filename	Size	Change
website/build/assets/js/main.********.js	603 kB	+66 B (0%)

ℹ️ View Unchanged

Filename	Size
website/.docusaurus/globalData.json	52.6 kB
website/build/assets/css/styles.********.css	106 kB
website/build/index.html	38.9 kB

_{compressed-size-action}

[netlify]

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[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	PWA	Report
/	🟠 84	🟢 100	🟢 100	🟢 100	🟢 90	Report
/docs/installation	🟠 84	🟢 100	🟢 100	🟢 100	🟢 90	Report

[slorber]

LGTM 👍

That could be nice to add tests some basic "load()" tests that we currently don't have

I'm thinking of something simple like this?

import loadSetup from '../../server/__tests__/testUtils';

describe('load site', () => {
  it('simple', async () => {
    const props = await loadSetup('simple');
    expect(props).toMatchSnapshot()
  });

  it('custom', async () => {
    const props = await loadSetup('simple');
    expect(props).toMatchSnapshot()
  });

  it('i18n', async () => {
    const props = await loadSetup('i18n');
    expect(props).toMatchSnapshot()
  });
});

Also worth adding tests on the docs plugin, where you make a fixture use like i18n-custom/fr-custom or something?

[slorber]

thanks 👍