wasm shim image env var name does not match deployment var name

[eguzki]

What

Fixes #128

The deployment objects sets RELATED_IMAGE_WASMSHIM

 env:                                                   
   - name: RELATED_IMAGE_WASMSHIM                         
     value: "oci://quay.io/kuadrant/wasm-shim:v0.1.0"     
 image: controller:latest                               

But the code was reading WASM_FILTER_IMAGE

Verification Steps

run dev env

make local-env-setup

Run Operator's controllers with the env var name expected RELATED_IMAGE_WASMSHIM

RELATED_IMAGE_WASMSHIM=oci://quay.io/kuadrant/wasm-shim:v0.1.0 make run

Create kuadrant CR

k apply -f - <<EOF
---
apiVersion: kuadrant.kuadrant.io/v1beta1
kind: Kuadrant
metadata:
  name: kuadrant-sample
spec: {}
EOF

Create some HTTPRoute and RLP

k apply -f examples/toystore/httproute.yaml
k apply -f examples/toystore/ratelimitpolicy_httproute.yaml

Check wasmplugin for the wasm shim URL

k get WasmPlugin -n istio-system kuadrant-istio-ingressgateway -o jsonpath="{.spec.url}" | yq e -P
oci://quay.io/kuadrant/wasm-shim:v0.1.0

It should be oci://quay.io/kuadrant/wasm-shim:v0.1.0 instead of the latest oci://quay.io/kuadrant/wasm-shim:latest