Added authenication/authorization. Refactored api startup.

JSMR.UI.Blazor/Pages/Login.razor

@@ -0,0 +1,86 @@
+@page "/login"
+
+@using JSMR.UI.Blazor.Services
+
+@inject SessionState Session
+@inject NavigationManager Nav
+
+<h3>Login</h3>
+
+@if (Session.IsAuthenticated)
+{
+    <p>You're already logged in as <b>@Session.Me?.name</b>.</p>
+    <button @onclick="Logout">Logout</button>
+}
+else
+{
+    <div style="max-width: 360px;">
+        <div>
+            <label>Username</label><br />
+            <input @bind="username" />
+        </div>
+        <div style="margin-top: 8px;">
+            <label>Password</label><br />
+            <input type="password" @bind="password" />
+        </div>
+
+        <div style="margin-top: 12px;">
+            <button @onclick="LoginAsync" disabled="@busy">Login</button>
+        </div>
+
+        @if (!string.IsNullOrWhiteSpace(error))
+        {
+            <p style="color: crimson; margin-top: 8px;">@error</p>
+        }
+    </div>
+}
+
+@code {
+    private string username = "";
+    private string password = "";
+    private bool busy;
+    private string? error;
+
+    private async Task LoginAsync()
+    {
+        busy = true;
+        error = null;
+        try
+        {
+            var ok = await Session.LoginAsync(username, password);
+            if (!ok)
+            {
+                error = "Invalid username or password.";
+                return;
+            }
+
+            Nav.NavigateTo("/");
+        }
+        catch (Exception ex)
+        {
+            error = ex.Message;
+        }
+        finally
+        {
+            busy = false;
+        }
+    }
+
+    private async Task Logout()
+    {
+        busy = true;
+        error = null;
+        try
+        {
+            await Session.LogoutAsync();
+        }
+        catch (Exception ex)
+        {
+            error = ex.Message;
+        }
+        finally
+        {
+            busy = false;
+        }
+    }
+}