Fix base-image resultion error

Currently the build of base-images fails due to potential dependency
confusion. The patch resolves the issue by providing a full qualified
image name.

Error message:
```
STEP 1: FROM nginx:alpine
Error: error creating build container: short-name resolution enforced but cannot prompt without a TTY
```

Reference:
https://github.com/containers/podman/issues/10492

Dockerfile

-FROM nginx:alpine
+FROM docker.io/library/nginx:alpine
 
 COPY ./nginx.d/*.conf /etc/nginx/conf.d/