Relay: replace `@adeira/fetch` dependency with simple `cross-fetch`

[mrtnzlml]

The purpose of this change is to replace @adeira/fetch dependency used in src/relay/ project with a simple cross-fetch dependency (this will remove fetchTimeout and retryDelays functionality so a small refactoring will be needed).

Acceptance criteria

1. The project located in src/relay/ no longer uses @adeira/fetch (replaced with cross-fetch).
2. The PR follows the project conventions.
3. All CI checks pass, and all code review comments are addressed.

Hits for successful completion of this task

1. Replace @adeira/fetch with cross-fetch in src/relay/package.json (run ./x install to install this new dependency).
2. Make the necessary changes in src/relay/ to use this new dependency.
3. If needed, update other dependent projects in this monorepo as well (see the failing tests).

How to install and run this project

git clone --depth=100 [email protected]:adeira/universe.git
cd universe
corepack enable

chmod +x ./x
./x install

To run JavaScript tests:

./x tests

For more information, please visit README.md located at the root of this project. If you get lost, you can also start a new discussion. 😎