[Ubuntu] Migrate PowerShell and Docker tests to Pester (#2317)

* PowerShell and Docker Pester tests

* no pester module

* import pester

* invoke docker with sudo

* remove native test

* add fix for az 1.0.0 module

* revert powershellget installation

* revert flag Force

* add $ProgressPreference = "SilentlyContinue"

images/linux/scripts/installers/Install-AzureModules.ps1

@@ -0,0 +1,31 @@
+$ErrorActionPreference = "Stop"
+$ProgressPreference = "SilentlyContinue"
+
+Import-Module "$env:HELPER_SCRIPTS/Tests.Helpers.psm1" -DisableNameChecking
+
+# Get modules content from toolset
+$modules = (Get-ToolsetContent).azureModules
+$installPSModulePath = "/usr/share"
+
+foreach ($module in $modules)
+{
+    $moduleName = $module.name
+    Write-Host "Installing ${moduleName} to the ${installPSModulePath} path..."
+    foreach ($version in $module.versions)
+    {
+        $modulePath = Join-Path -Path $installPSModulePath -ChildPath "${moduleName}_${version}"
+        Write-Host " - $version [$modulePath]"
+        Save-Module -Path $modulePath -Name $moduleName -RequiredVersion $version -Force -Verbose
+    }
+}
+
+# If Az.Accounts > 1.0.0 unable to load module with error: Assembly with same name is already loaded
+# Force install Az.Accounts 1.0.0
+$azAccountsPath = "/usr/share/az_1.0.0/Az.Accounts"
+if (Test-Path $azAccountsPath)
+{
+    Remove-Item -Path $azAccountsPath -Force -Recurse
+    Save-Module -Name Az.Accounts -Path "/usr/share/az_1.0.0" -RequiredVersion 1.0.0 -Force
+}
+
+Invoke-PesterTests -TestFile "PowerShellModules" -TestName "AzureModules"