sombrero: Add agenix module and use it for pinwheel ssh key

secrets/pinwheel/alex.pinwheel-sombrero.pub.age

@@ -1,10 +1,12 @@
 age-encryption.org/v1
--> ssh-ed25519 vxPbZg p4V0jEUSH1GQeHcqAzKQVyQb1whfOdBQ1FM+Y3UCeXI
-N6kWm/X+OdIaaipDDCPgM1bHjj3RxBOGf+E/PhJJRR8
--> ssh-ed25519 ek+b7Q iYAYLpirJ/ftOLuu+K7NAVEBXPsINGet+vyjsjTzp1w
-bal6VjX/5iOaJSXVI9T1pJWB3Pk0ees1mhMpdU6lgMc
--> be:Y?D<-grease k$wtP
-kVG6hZ/k+y3O5X9rDF0v1FuNSrKDH1dPgVY20yZwT43Tkhzb59DaNHYKHVrBhYVH
-RWACoa7MP4LE7d6y5URUkcSk1PGKt9s7SbwuH9ExKZM+1z8
---- MtZ6IZYpKhgghsljQXY/psDJVufYuG2E/s5/cpuUsWU
-s6<EFBFBD>:?<3F>g<EFBFBD><67><<3C>^yNH<<3C><>}<7D><><02>„4<0B><>d¬FB(-<2D>\<[W<><57><EFBFBD><19><>3Xԙ<58><D499><EFBFBD><EFBFBD><EFBFBD>6L}<7D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><06><> gP<67>u<EFBFBD>&<26> 3<>MWZ<57>T<>kM<6B><4D><EFBFBD><EFBFBD>ϱ*h<>[<5B><>y<EFBFBD>rR<72><52><EFBFBD>*p<><70>z<EFBFBD><7A><EFBFBD><EFBFBD><EFBFBD>߃<EFBFBD><DF83>:<0F><><EFBFBD><EFBFBD><EFBFBD>e
+-> ssh-ed25519 vxPbZg 1xoU/lpkuPdG+UQW1D9VrAnSSEpK+b6pu+wflgvRQFs
+7jupzfqRmH5wzcVX3VCqQAghHZNXHiPc6YP8es8NYic
+-> ssh-ed25519 MxZlmA QUqt2gwCtIUv8nFTr8LSinLt7hD05EH/N6Yobew6GEI
+JuzbNQrpONfKkIUgi//p8LhwxjCka/SQGYimglCueCU
+-> ssh-ed25519 ek+b7Q AfW7nec0E1vtg72C1f2Qp7RM/qNf19x5eEZgsonXbCs
+joytWP1pp8lAgm2ORh88ETi8giGwPfCo9mwtlqTQ0U8
+-> M,fSDC$-grease {.x R26(e2' v5Y
+5JMhlzqPlW0vBFTe/5gBoSqxHesiKDi9BZp7Ckf+c6P2NiJHe3yurg+l8XoxEjN9
+GQrQTg
+--- luPA8khtSQv2Kg8v+GWx8BPXPqeqcnoiGfghMJqDFuE
+픖~&l<>+I9<49><39>xϞ<78>߼DV<03><06>r<EFBFBD>W<EFBFBD><57>AX r<>i<EFBFBD>Y