[WebIDE] Create a Web IDE deployment diagram that communicates information flow

Problem to solve

Customers want a source of information that describes how data flows between the GitLab instance origin and the extension host domain origin.

Proposed solution

Create a Web IDE runtime architecture sequence diagram that describes how the different origins used by the Web IDE communicate with each other.

Acceptance criteria

• Create a Web IDE runtime architecture sequence diagram that describes how the different origins used by the Web IDE communicate with each other.

Implementation plan