Create package for Salesforce integration

[akshay-saraswat]

We must migrate Salesforce filebeat module to agent-based integration so that we boost agent/fleet adoption and are ready for any decision related to beats future.

cc: @pmeresanu85 @rameshelastic

All changes

• Change follows the contributing guidelines
• Supported versions of the monitoring target are documented
• Supported operating systems are documented (if applicable)
• Integration or System tests exist
• Documentation exists
• Fields follow ECS and naming conventions
• At least a manual test with ES / Kibana / Agent has been performed.
• Required Kibana version set to:

[yug-rajani]

List of backlog items as suggested by @agithomas and discussed with the team:

• System tests with actual Salesforce instance containerized (Currently, the system tests use the observability/stream image due to the limitations mentioned here)

CC: @milanparmar-crest @lalit-satapathy