[RFE] support "custom" namespaces about caikit-tgis-serving

[Jooho]

The doc is updated. please try it again.

[thoraxe]

It now includes problems with service mesh as non-admin users cannot modify the SMMR resources:

export TEST_NS=caikit-ej2
oc new-project ${TEST_NS}
sed "s/<test_ns>/$TEST_NS/g" custom-manifests/service-mesh/smmr-test-ns.yaml | tee ./smmr-current.yaml | oc -n istio-system apply -f -
sed "s/<test_ns>/$TEST_NS/g" custom-manifests/service-mesh/peer-authentication-test-ns.yaml | tee ./peer-authentication-test-ns-current.yaml | oc apply -f -
Now using project "caikit-ej2" on server "https://api.aisrhods-odh.8s6u.p1.openshiftapps.com:6443/".

You can add applications to this project with the 'new-app' command. For example, try:

    oc new-app rails-postgresql-example

to build a new example application in Ruby. Or use kubectl to deploy a simple Kubernetes application:

    kubectl create deployment hello-node --image=registry.k8s.io/e2e-test-images/agnhost:2.43 -- /agnhost serve-hostname

Error from server (Forbidden): error when retrieving current configuration of:
Resource: "maistra.io/v1, Resource=servicemeshmemberrolls", GroupVersionKind: "maistra.io/v1, Kind=ServiceMeshMemberRoll"
Name: "default", Namespace: "istio-system"
from server for: "STDIN": servicemeshmemberrolls.maistra.io "default" is forbidden: User "[email protected]" cannot get resource "servicemeshmemberrolls" in API group "maistra.io" in the namespace "istio-system"
peerauthentication.security.istio.io/default created

[Jooho]

This issue fixed with this PR(#28)