AzureRm cmdlets should support wildcards where appropriate

[pcgeek86]

The -Name parameter for Get-AzureRmRoleDefinition should support wildcards, so that the user doesn't have to remember the exact name of each ARM RBAC Role.

Cheers,
Trevor Sullivan
Microsoft MVP PowerShell
http://trevorsullivan.net
http://twitter.com/pcgeek86

[cormacpayne]

Closing in favor of #5447