[Feat]: Change enviroment env CHECK_UPDATE_INTERVAL to be configured in a .env file

[rodbecc]

Is your feature request related to a problem? Please describe.
To avoid cluttering the shell config file with our enviroment envs, it would be nice to have a .env file and a .env.example file.

Describe the solution you'd like

• Include a a .env.example file and add .env file to .gitignore;
• Include instructions about it on the README.md;
• Create tests file for this feature;