feat: starlark -> plan (#2338)

## Description
Renames mentions of Starlark to Plan so first time users unaware of
Starlark don't need to understand it to perform flows such as enclave
building and running packages for the first time.

## Is this change user facing?
YES

core/server/api_container/server/startosis_engine/startosis_runner.go

@@ -28,7 +28,7 @@ type StartosisRunner struct {
 const (
  defaultCurrentStepNumber = 0
  defaultTotalStepsNumber = 0
- startingInterpretationMsg = "Interpreting Starlark code - execution will begin shortly"
+ startingInterpretationMsg = "Interpreting plan - execution will begin shortly"
  startingValidationMsg = "Starting validation"
  startingExecutionMsg = "Starting execution"
 )

enclave-manager/web/packages/app/src/emui/enclaves/components/enclaveBuilder/modals/ViewStarlarkModal.tsx

@@ -21,7 +21,7 @@ export const ViewStarlarkModal = ({ isOpen, onClose, starlark }: ViewStarlarkMod
  <Modal closeOnOverlayClick={true} isOpen={isOpen} onClose={onClose} isCentered>
  <ModalOverlay />
  <ModalContent minW={"800px"} maxH={"90vh"}>
- <ModalHeader>Previewing Starlark</ModalHeader>
+ <ModalHeader>Previewing Plan</ModalHeader>
  <ModalCloseButton />
  <ModalBody minH={"70vh"} flex={"1 1 auto"} overflowY={"auto"}>
  {isDefined(starlark) && <FileDisplay value={starlark} title={"main.star"} filename={`main.star`} />}