#2540 - implemented safeSet for useLocalStorage

[geanify]

Description

As per issue #2540 I implemented a separate functionality for people who don't want to overwrite items already existing in their localStorage.

safeSet will print out a warning when attempting to use set over an existing value

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as before)

Checklist

• [x] Read the Contributing Guide
• [x] Perform a code self-review
• [x] Comment the code, particularly in hard-to-understand areas
• [x] Add documentation
• [x] Add hook's story at Storybook
• [x] Cover changes with tests
• [x] Ensure the test suite passes (yarn test)
• [x] Provide 100% tests coverage
• [x] Make sure code lints (yarn lint). Fix it with yarn lint:fix in case of failure.
• [x] Make sure types are fine (yarn lint:types).