feat(wes): add SDK support

[uniqueg]

Add SDK support foor the GA4GH Workflow Execution Service (WES) API, version 1.1.0.

This issue requires addressing the following steps:

• In the ./lib/src/clients/wes folder, and based on the models added in feat(wes): add models #49, implement a module with client methods for communicating with the WES API; these include methods for
  • creating runs
  • listing runs
  • cancelling runs
  • getting the status of a run
  • showing details of a run
  • fetching outputs of a run
• Document your code; use the TES client as a template/example
• Provide unit tests for your code; again, use the available TES client as a template/example

Additional context

• This issue is part of meta issue feat(wes): add support for the GA4GH WES API #48. Refer to it for context and additional information.
• This issue requires feat(wes): add models #49 to be addressed first.