Prevent prompt to login again, if already logged in. Provide default …

[drwill-ms]

…parameters that will work for Azure Function deployment.

Purpose

• Do not prompt to login to Azure if the user is already logged in.
• Update template.json with good defaults (assuming no name conflicts exist) so the template runs fine out of the box, and parameter descriptions to parameters.json.

Does this introduce a breaking change?

[ ] Yes
[x] No

Pull Request Type

What kind of change does this Pull Request introduce? !-- Please check the one that applies to this PR using "x". -->

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe:

How to Test

• Get the code

git clone [repo-address]
cd [repo-name]
git checkout [drwill/AzureFuncArmProvision]

• Test the code

  
  // In PowerShell:
  cd AzureDataFactory\arm-template-azure-function-app
  .\deploy.ps1 <with parameters including unique rg>
  // Confirm prompted to login

// Manually login Login-AzureRmAccount .\deploy.ps1 <with parameters including unique rg and -parametersFilePath ""> // Confirm not prompted to login again

## What to Check
Verify that the following are valid
* No errors during provision
* Resources appear in specified Azure subscription and resource group

## Other Information
The login check is standard code I've used before.

I thought it would be helpful, in case someone didn't edit/include the parameters.json file, that the deployment might work out of the box.