Allow for multi-region setups and added Error Handling

[silvanm]

Changes

• Initialization: Implemented top-level async initialization with global variables for better state management
• File System: Added robust path resolution and detailed error handling for key file access
• Location Validation: Added comprehensive list of valid BigQuery locations and switched default to 'EU'
• Error Handling: Enhanced error messages with specific details for different failure scenarios

These changes improve reliability and provide better feedback for configuration issues.

[0anton]

I‘m not the code owner, but this PR is lgtm.

[ngohuuduc]

This change is not yet merge ?

[silvanm]

As suggested in #4 (comment) I have now pushed the following changes:

1. Removed Location Validation:

• Removed the list of valid BigQuery locations that was previously used for validation
• Removed the validation check that would throw an error if an invalid location was provided

2. Changed Default Location:

• Changed the default location from 'EU' to 'US'

[ngohuuduc]

Hello, I have clone the project from @silvanm and tried to run it on my local. The tsconfig.json needs to be updated as well to handle for some

"module": "NodeNext" → Allows top-level await in Node.js.

"moduleResolution": "NodeNext" → Required when using "module": "NodeNext".

"target": "ES2022" → Ensures modern JavaScript syntax is used.