Add env variable for which branch to use. Move CPU and RAM requirements to env so that only 1 docker-compose.yml example is needed.

Config/Hyperling.com/env.example

@@ -7,3 +7,18 @@
 # Subsequent builds consistently take less than 2 seconds.
 # Testing was done on the micro server, not a workstation.
 COMPOSE_BAKE=true
+
+## Branch ##
+# Allow choosing the branch. By keaving it blank, main will be used.
+# Should be in the full "--branch my-branch" syntax.
+BRANCH=
+#BRANCH="--branch dev"
+
+## Performance ##
+# Standard Server
+CPU=0.25
+MEM=0.25G
+# Micro Server
+# 2023-01-24 container needs 128M to get started fully then settles to 25M.
+CPU=0.10
+MEM=128M