Add WRF build guide (#177)

Add a section to the docs for building applications that are not in the
list of supported software.

Add a first entry:
https://docs.tds.cscs.ch/177/build-install/applications/wrf/#wrf

---------

Co-authored-by: Rocco Meli <[email protected]>
Co-authored-by: Mikael Simberg <[email protected]>

Author: 3 people

.github/actions/spelling/allow.txt

@@ -11,6 +11,7 @@ CHF
 COSMA
 CPE
 CPMD
+CRYOWRF
 CWP
 CXI
 Ceph
@@ -324,6 +325,7 @@ wikitext
 wlcg
 workaround
 workflows
+wrf
 xattr
 xattrs
 xcb

docs/build-install/applications/matlab.md

@@ -0,0 +1,5 @@
+[](){#ref-software-packages-matlab}
+# Matlab
+
+CSCS does not have a license to provide [Matlab](https://www.mathworks.com/products/matlab.html) to users on Alps.
+Users or groups with valid licenses can install Matlab themselves as [user software][ref-support-user-apps].