FT connector: use config instead of `.env` for public data

[sept-en]

Currently, deployment and usage of Hardhat scripts for FT connector use .env file as a source for the contract addresses, etc. The .env file is currently in the git, and this could lead to an accidental mistake pushing the private keys/API keys to GitHub. This needs to be changed so:

• Addresses are used from the config files that are public and tracked;
• .env file contains only sensitive data: API keys, private keys, etc;
• .env file is removed from the tracked files.