feat: Add WES API endpoint information to agc context describe output

[a-li]

Issue #, if available:
fixes #220

Description of Changes
Add the WES API endpoint url for a context as part of the output from agc context describe <context-name>

Before Change:

demo-wdl-project % agc context describe spotCtx          
2022-01-03T22:20:23-08:00 𝒊  Describing context 'spotCtx'
CONTEXT	256	spotCtx	true	STARTED	
OUTPUTLOCATION	s3://agc-586466483460-us-east-2/project/Demo/userid/dzl3501BW/context/spotCtx

After Change:

demo-wdl-project % agc context describe spotCtx        
2022-01-03T22:20:23-08:00 𝒊  Describing context 'spotCtx'
CONTEXT	256	spotCtx	true	STARTED	
OUTPUTLOCATION	s3://agc-586466483460-us-east-2/project/Demo/userid/dzl3501BW/context/spotCtx
WESENDPOINT	https://k5jirhe0rk.execute-api.us-east-2.amazonaws.com/prod/ga4gh/wes/v1

Description of how you validated changes
Activate account, deploy several contexts and ran agc context describe and the WESENDPOINT entry with the correct endpoint is populated.

Checklist

• If this change would make any existing documentation invalid, I have included those updates within this PR
• I have added unit tests that prove my fix is effective or that my feature works
• I have linted my code before raising the PR
• Title of this Pull Request follows Conventional Commits standard: https://www.conventionalcommits.org/en/v1.0.0/

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