Update .env.template with placeholders

[tectonia]

Replaces the following hardcoded vaules in docker/.env.template with placeholders:

• AZURE_CLIENT_ID,

• AZURE_CLIENT_SECRET,

• AZURE_TENANT_ID,

• DataHubFhirServer__TemplateImage

• Tests

• Documentation

[liammoat]

Thanks for picking this up 👍

[gaurarpit]

i am just thinking, they will always now be in the git commit history. so, anyone can go back and look.
I am not blocking this PR and approving it, but, let's chat about this topic. I dont know what the right solution would be. Let's brainstorm.

[gaurarpit]

One comment that I want to discuss. rest LGTM.

[tectonia]

i am just thinking, they will always now be in the git commit history. so, anyone can go back and look. I am not blocking this PR and approving it, but, let's chat about this topic. I dont know what the right solution would be. Let's brainstorm.

Client ID and tenant ID are not secrets per se. They are discoverable knowing domain name to anyone on the internet I believe. @liammoat correct me if I'm wrong please.

[liammoat]

i am just thinking, they will always now be in the git commit history. so, anyone can go back and look. I am not blocking this PR and approving it, but, let's chat about this topic. I dont know what the right solution would be. Let's brainstorm.

Client ID and tenant ID are not secrets per se. They are discoverable knowing domain name to anyone on the internet I believe. @liammoat correct me if I'm wrong please.

Yeah - no major concerns from me with these being in the history.

[tectonia]

Unfortunately, the template tests do not succeed with placeholder values. We should investigate further why. I will abandon this PR and raise a work item separately.