This is a follow-up to #32693, which missed a bunch of places due to
varying ways of typing Azure AD. (Azure AD, Azure Active Directory etc.)
In the diff there's an apparent inconsistency with renaming, in some
places renaming to just "Microsoft Entra ID" and in others
"Microsoft Entra ID (AzureAD)".
The idea is to add (AzureAD) in ordinary documentation, as it can help
clarity since many people still think of this as AzureAD, while sticking
with brevity and cleanliness of just using the official name in
marketing focused material.
Microsoft has been renaming AzureAD to Entra ID. Though both names still
seem to function, even if unofficially, so this mostly renames to `Entra
ID (AzureAD)` to reference both for clarity.
These files are not Jinja2 templates, so there's no reason that they needed
to be inside `templates/zerver`. Moving them to the top level reflects their
importance and also makes it feel nicer to work on editing the help center content,
without it being unnecessary buried deep in the codebase.
