Add "Open in IdentityNow" command

[yannick-beot-sp]

On the tenant, it should be possible to quickly open the Web interface of IdentityNow. No SSO is expected. Just the capacity to quickly jump in IdentityNow can be applied to:

• Tenant -> Home page of IdentityNow
• Sources and Workflows
• Specific Source or specific Workflow, Provisioning Policies

From a technical point of view, the code of the extension is quite simple:

vscode.commands.executeCommand('vscode.open', vscode.Uri.parse(url));

The same "common" approach as the "Open" command should be kept to minimize the code/number of commands. This means that the models for the tree (Data Provider) should be updated to have a "generic" url.