client/web: add subnet routes view

Add UI view for mutating the node's advertised subnet routes.

Updates #10261

Signed-off-by: Sonia Appasamy <sonia@tailscale.com>

client/web/src/assets/icons/clock.svg

@@ -0,0 +1,11 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<g clip-path="url(#clip0_14876_118476)">
+<path d="M8.00065 14.6667C11.6825 14.6667 14.6673 11.6819 14.6673 8.00004C14.6673 4.31814 11.6825 1.33337 8.00065 1.33337C4.31875 1.33337 1.33398 4.31814 1.33398 8.00004C1.33398 11.6819 4.31875 14.6667 8.00065 14.6667Z" stroke="#706E6D" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
+<path d="M8 4V8L10.6667 9.33333" stroke="#706E6D" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
+</g>
+<defs>
+<clipPath id="clip0_14876_118476">
+<rect width="16" height="16" fill="white"/>
+</clipPath>
+</defs>
+</svg>

client/web/src/assets/icons/plus.svg

@@ -0,0 +1,4 @@
+<svg width="20" height="20" viewBox="0 0 20 20" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M10 4.16663V15.8333" stroke="white" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
+<path d="M4.16602 10H15.8327" stroke="white" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
+</svg>