Enable parallel installation and uninstallation by considering combination of site, app and environment ids

Issue Summary

With the custom environment concept, partners hoped to be able to get rid of the locking. But whenever concurrently a second forge --install command is triggered for the same app and at the same site (not the same environment!), the install is not performed with the following error:

CDAC query for details - 

https://community.developer.atlassian.com/t/un-install-in-parallel-to-multiple-muoa-custom-environments/78501 

Steps to Reproduce

Concurrently install/uninstall the same app with different environment ids to same site 

Expected Results

There should be no error as the combination of site, app and environment id is unique

Actual Results

The below exception is thrown in the CLI:

Error: Installation error: Task any-task-id conflicts with another pending or in progress task. (requestId: any-request-id) 

Workaround

Include environment id into consideration for blocking concurrent installs/uninstalls