stdlib: put full definition of #Op behind a build attribute

This allows dagger.io/dagger/op.#Op to be maintained in regular
uncommented CUE, but not participate by default in normal dagger
evaluation (given the performance problems it currently introduces).

The "full" #Op can be enabled by passing the "-t fullop" flag:

    cue eval -t fullop ./examples/react

(which currently triggers the performance issue).

Signed-off-by: Paul Jolly <paul@myitcv.io>

stdlib/dagger/op/op_fullop.cue

@@ -0,0 +1,17 @@
+@if(fullop)
+
+package op
+
+// Full resolution schema enforciong the complete op spec
+#Op: (#Export |
+	#FetchContainer |
+	#PushContainer |
+	#FetchGit |
+	#Exec |
+	#Local |
+	#Copy |
+	#Load |
+	#Subdir |
+	#WriteFile |
+	#Mkdir |
+	#DockerBuild) & {do: string}