EI needs to be updated to MI

https://github.com/wso2/reference-architecture/blob/master/digital-enterprise-k8s-wso2-api-platform.md

**Description:**
Since EI has gone to End of Life this page needs to be updated to MI.

**Suggested Labels:**
Low


**Affected Product Version:**
EI 6.6.0
APIM 4.0/4.1/4.2

