wip(shared): Changes to layouts

This will break the org build, but we need to rip out sanity anyway so
I don't think it's worth obsessing over it now.

I've essentially changes the default layout and added a new navigation
component.

sites/shared/components/base-layout.mjs

@@ -0,0 +1,36 @@
+/*
+ * The default full-page FreeSewing layout
+ */
+export const BaseLayout = ({ children = [] }) => (
+  <div className="flex flex-row items-start mt-8 w-full justify-between 2xl:px-36 xl:px-12 px-4">
+    {children}
+  </div>
+)
+
+/*
+ * The left column of the default layout
+ */
+export const BaseLayoutLeft = ({ children = [] }) => (
+  <div className="max-w-96 w-1/4 mt-8 hidden lg:block shrink-0">{children}</div>
+)
+
+/*
+ * The right column of the default layout
+ */
+export const BaseLayoutRight = ({ children = [] }) => (
+  <div className="max-w-96 w-1/4 mt-8 hidden xl:block">{children}</div>
+)
+
+/*
+ * The main column for prose (text like docs and so on)
+ */
+export const BaseLayoutProse = ({ children = [] }) => (
+  <div className="grow w-full m-auto max-w-prose mt-0 mb-8">{children}</div>
+)
+
+/*
+ * The central column for wide content (no max-width)
+ */
+export const BaseLayoutWide = ({ children = [] }) => (
+  <div className="grow w-full m-auto mt-0 mb-8 grow">{children}</div>
+)