boards: v2: Add documentation index for converted boards

Adds documentation pages for rp2040-converted boards

Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>

boards/index.rst

@@ -31,7 +31,9 @@ available under :zephyr_file:`doc/templates/board.tmpl`.
    v2/adafruit/index.rst
    v2/altera/index.rst
    v2/arm/index.rst
+   v2/gaisler/index.rst
    v2/gd/index.rst
+   v2/qemu/index.rst
    v2/raspberry_pi/index.rst
    v2/renesas/index.rst
    v2/sparkfun/index.rst

boards/v2/gaisler/index.rst

@@ -0,0 +1,10 @@
+.. _boards-gaisler:
+
+Frontgrade Gaisler
+##################
+
+.. toctree::
+   :maxdepth: 1
+   :glob:
+
+   **/*

boards/v2/qemu/index.rst

@@ -0,0 +1,10 @@
+.. _boards-qemu:
+
+QEMU
+####
+
+.. toctree::
+   :maxdepth: 1
+   :glob:
+
+   **/*