Add Create Account command for web support

[alexweininger]

Fixes #643

In web, we can no longer rely on the Create Account command contributed by the Azure Account extension. Instead I added another generic command that on desktop will use the Azure Account command and on web will just open the link.

Now that I write this I guess we could just always open the link ourselves and not use the Azure Account extension command at all.

Ok, updated the changes so that we're not relying on AA for this, and just opening the link in RGs.

[alexweininger]

Never mind Nathan beat me to it https://github.com/microsoft/vscode-azureresourcegroups/pull/645

[nturinski]

https://github.com/microsoft/vscode-azureresourcegroups/pull/645

[nturinski]

I even used your aka.ms link lol

[alexweininger]

I even used your aka.ms link lol

Now that's teamwork!