Readme Infura links update

### What is this about?

In the readme section of local machine build we have instruction on how to setup Infura key. Since Infura moved to developer.metamask.io some of the links redirect to default docs instead of specific page.

Would suggest changing Infura API Key link to: https://docs.metamask.io/services/get-started/infura/
and register page to https://developer.metamask.io/

### Scenario

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### Design

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### Technical Details

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### Threat Modeling Framework

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### Acceptance Criteria

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### Stakeholder review needed before the work gets merged

- [ ] Engineering (needed in most cases)
- [ ] Design
- [ ] Product
- [ ] QA (automation tests are required to pass before merging PRs but not all changes are covered by automation tests - please review if QA is needed beyond automation tests)
- [ ] Security
- [ ] Legal
- [ ] Marketing
- [ ] Management (please specify)
- [ ] Other (please specify)

### References

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Start in the README's local machine build section, where the Infura API key and registration links are documented. Update those two URLs to the destinations given in the issue, then verify that the README shows the new links and that they open the intended pages.

Written by the indexing model from the issue text.