feat: add environment configuration support

- Introduced .env.example file to provide a template for environment variables.
- Updated .gitignore to exclude .env files from version control.
- Implemented loadEnvFile function in client.ts to load environment variables from a .env file into process.env, enhancing configuration management.

.gitignore

@@ -11,5 +11,4 @@ oclif.manifest.json
 
 yarn.lock
 package-lock.json
-
-
+.env