make setup-aws-creds fails with missing kubectl

[Schnitzel]

make setup-aws-creds does not use the on the fly installed kubectl, so if you don't have kubectl it fails:

$ make setup-aws-creds
make[1]: Entering directory '/home/ec2-user/k0rdent-demos'
envsubst < setup/aws-credentials.yaml | kubectl apply -f -
/bin/bash: line 1: kubectl: command not found

[soerenschneider]

I only changed two lines of code in this PR to use a dockerized kubectl. No need to check versions, download, check signatures, etc.

So far only tested with a couple of (random) Makefile targets, also has room for improvements, for instance

• not use the host network, instead use the "kind" network
• maybe replace the image

I'd like to hear opinions first before going down that road. @Schnitzel @Algeran

[Algeran]

I would prefer not to use containerized kubectl due to we use it a lot and start container each time to execute the kubectl command will increase the execution time of all demos significantly (take into account that not everyone run it on Mac M2 laptops). Additionally, for kubectl we use:

• templates, manifests. Here we need to make sure that all required directories attached via volumes
• in combination with envsubst, yq calls - here we need to make sure that these binaries exist in kubectl container. If envsubst is the built-in tool, the yq is not and more likely you will come with the solution where you will install yq each time during the kubectl execution or will build some custom container with kubectl and yq

It's fine to use containers for some commands instead of downloading binaries if we use them 1-2 times during the whole demo (like openssl).

For the particular issue we just forgot to replace kubectl with $(KUBECTL) in couple places.

[Algeran]

I fixed and closed this issue to unblock demos. To continue usage of containerized binaries discussion, please create the separate issue