Hardhat-network-helpers: TODOs as soon as V3 node is ready

[ChristopherDedominici]

Currently the tests are only available in manual mode on the local machine because the Hardhat node for V3 is not available yet.
As soon as the Hardhat V3 node is ready, this can be addressed.

TODOs for the hardhat-network-helpers:

• delete the ./run-tests.ts file
• delete the pnpm test:tmp command
• update the initializeNetwork helper function at the path ./test-tmp/helpers/helpers.ts
• move the tests from the test-tmp folder to the test folder and delete the test-tmp folder
• update the tests that are using the allow-blocks-same-timestamp property

TODOs for the example project:

• Remove the comment in the scrip ./scripts/network-helpers.ts that explains how to run with a V2 node

All the checked tasks are addressed here.

The task regarding allow-blocks-same-timestamp is missing because the property is not implemented yet.