Add Salesforce Authentication Module with OAuth and Password Support

[srijan-chaudhuri]

Description:

We need to implement a Salesforce authentication module that supports both OAuth2 and password-based login mechanisms. The module should handle token refreshes for OAuth2, support retry logic for retriable errors, and provide a way to select the correct authentication method based on the provided configuration.

Acceptance Criteria:

• Implement a base authentication class SalesforceAuth that handles:
  • Access tokens
  • Instance URL
  • Headers for REST and bulk API calls

QA and Testing:

• Test OAuth2 login using valid credentials.
• Test password-based login using valid credentials.
• Test automatic token refresh functionality for OAuth2.
• Test retry logic for expired tokens or other retriable errors.
• Test error handling and logging for invalid credentials.

Related PR:

• Link to the corresponding PR once created.