added security attribute to TenantController Get methods and resolved TenantId on server during Installation

Oqtane.Server/Controllers/SiteController.cs

@@ -50,7 +50,10 @@ namespace Oqtane.Controllers
                 bool authorized;
                 if (!Sites.GetSites().Any())
                 {
-                    authorized = true; // provision initial site during installation
+                    // provision initial site during installation
+                    authorized = true; 
+                    Tenant tenant = Tenants.GetTenant();
+                    Site.TenantId = tenant.TenantId;
                 }
                 else
                 {

Oqtane.Server/Controllers/TenantController.cs

@@ -22,6 +22,7 @@ namespace Oqtane.Controllers
 
         // GET: api/<controller>
         [HttpGet]
+        [Authorize(Roles = Constants.HostRole)]
         public IEnumerable<Tenant> Get()
         {
             return Tenants.GetTenants();
@@ -29,6 +30,7 @@ namespace Oqtane.Controllers
 
         // GET api/<controller>/5
         [HttpGet("{id}")]
+        [Authorize(Roles = Constants.HostRole)]
         public Tenant Get(int id)
         {
             return Tenants.GetTenant(id);