Document feature flag ENABLE_ANONCRED

[FabioPinheiro]

Add the documentation about the feature flag ENABLE_ANONCRED
Related with:

• Feature request Feature flag for Anoncreds cloud-agent#1491
• PR feat: add feature flag to enable/disable support for Anoncred (backend job and API) #1491 cloud-agent#1492

[yshyn-iohk]

fixed in the PR #203
@FabioPinheiro, can we close the issue?

https://github.com/hyperledger-identus/docs/blob/main/documentation/home/identus/cloud-agent/environment-variables.md

[FabioPinheiro]

yes thx