Speed up net.sh builds (#16360)

* Speed up net.sh builds

* feedback

* Update net/net.sh

Co-authored-by: Tyera Eulberg <teulberg@gmail.com>

* feedback

* fix

Co-authored-by: Trent Nelson <trent.a.b.nelson@gmail.com>
Co-authored-by: Tyera Eulberg <teulberg@gmail.com>

net/net.sh

@@ -42,6 +42,7 @@ Operate a configured testnet
  startnode    - Start an individual node (previously stopped with stopNode)
  stopnode     - Stop an individual node
  startclients - Start client nodes only
+ prepare      - Prepare software deployment. (Build/download the software release)
  update       - Deploy a new software update to the cluster
  upgrade      - Upgrade software on bootstrap validator. (Restart bootstrap validator manually to run it)
 
@@ -185,12 +186,12 @@ build() {
 
     buildVariant=
     if $debugBuild; then
-      buildVariant=debug
+      buildVariant=--debug
     fi
 
     $MAYBE_DOCKER bash -c "
       set -ex
-      scripts/cargo-install-all.sh farf \"$buildVariant\"
+      scripts/cargo-install-all.sh farf $buildVariant --validator-only
     "
   )
 
@@ -1055,6 +1056,9 @@ start)
   prepareDeploy
   deploy
   ;;
+prepare)
+  prepareDeploy
+  ;;
 sanity)
   sanity
   ;;