[frontend] Implement list menu component (ISH-392)

Iceshrimp.Frontend/Components/Menu.razor

@@ -0,0 +1,18 @@
+
+@if (_display)
+{
+    <div class="menu">
+        @ChildContent
+    </div>
+}
+
+@code {
+    [Parameter] [EditorRequired] public required RenderFragment ChildContent { get; set; }
+    private                                      bool           _display;
+
+    public void Toggle()
+    {
+        _display = !_display;
+        StateHasChanged();
+    }
+}

Iceshrimp.Frontend/Components/Menu.razor.css

@@ -0,0 +1,11 @@
+.menu {
+    background-color: var(--foreground-color);
+    position: absolute;
+    padding: 0.5rem 1rem;
+    border-radius: 1rem;
+    border: var(--highlight-color) solid 0.1rem;
+    width: 13rem;
+    top: 2.5rem;
+    left: -5rem;
+
+}

Iceshrimp.Frontend/Components/MenuElement.razor

@@ -0,0 +1,16 @@
+@using Iceshrimp.Assets.PhosphorIcons
+
+<div @onclick="OnClick" class="menu-element">
+    <Icon Name="Icon"></Icon>
+    @Text
+</div>
+@code {
+    [Parameter] [EditorRequired] public required IconName             Icon     { get; set; }
+    [Parameter] [EditorRequired] public required RenderFragment       Text     { get; set; }
+    [Parameter] [EditorRequired] public required EventCallback OnSelect { get; set; }
+
+    private async Task OnClick()
+    {
+        await OnSelect.InvokeAsync();
+    }
+}

Iceshrimp.Frontend/Components/MenuElement.razor.css

@@ -0,0 +1,3 @@
+.menu-element {
+    display: flex;
+}