Community app migration to terms v5

[gondzo]

Community app needs to be migrated to v5 terms api (currently it is using the v2 api). Workflow is about the same as the v2 api, but using the v5 api token. Changes would likely be needed in community app and topcoder-react-lib (for the service calls) and include the following use cases:

• View term details
• Getting docusign url
• Handling docusign callback

cc @rootelement

[gondzo]

one more thing that would likely need to be updated is the private communities config - it has term ids hardcoded in the config - https://github.com/topcoder-platform/community-app/blob/f26ee94553fff5776fc7352f2d4b62449a7ce497/docs/how-to-add-a-new-topcoder-community.md