Static manifest generation uses kustomize instead of python

[afirth]

What this PR does / why we need it:

Currently, the static manifests are only compatible with K8s 1.20 APIs. This change generates static manifests for each supported version by calling helm template with the recently re-added --kube-version flag. In this PR, only 1.20 is targeted. #8000 adds the other versions, however based on feedback that this was too big to review, I split the PR.

Summary of changes

• static manifests are generated at 1.20 explicitly - this mimics the current unspecified behaviour
  • the various semverCompare statements are respected e.g. this one
• add_namespace.py (which also deleted spec.replicas) is removed
  • the manual steps in RELEASE are not required and are removed because the generated yaml retains the "standard" K8s format
  • helm --namespace is used to set the namespace
  • helm --kube-version is used to set the target version
  • kustomize is used to delete spec.replicas and add the namespace resource
    • New kustomize-deployment approach is super slow #4156 is not relevant as the generation is local
  • the inline heredocs in generate-deploy-scripts.sh and add-namespace.py move to yaml files whose directory layout matches that of the generated manifests

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• [?] New feature (non-breaking change which adds functionality)
• Documentation

Which issue/s this PR fixes

building blocks to fix #7810
relates #8000

How Has This Been Tested?

See #8000 (comment) - Basically by calling kustomize build > file on both the existing and new manifests and confirming there is no diff (besides the AWS NLB example changing name + location to a subfolder)

gco 2022-01-04-static-manifest-generation
gcb make-diffs

# checkout the manifests from main
git checkout main -- ./deploy/static
git reset

# deal with the one I moved
mkdir deploy/static/provider/aws/nlb-with-tls-termination
mv deploy/static/provider/aws/deploy-tls-termination.yaml deploy/static/provider/aws/nlb-with-tls-termination/deploy.yaml
cp deploy/static/provider/aws/kustomization.yaml deploy/static/provider/aws/nlb-with-tls-termination/

# run a hacky shell script which `kustomize builds` each directory using the existing kustomization.yaml
cat <<'EOF' > diffmaker.sh
#!/usr/bin/env bash
set -eux -o pipefail

#find . -type f -name deploy.yaml | xargs dirname
MANIFESTS=("./deploy/static/provider/do" "./deploy/static/provider/baremetal" "./deploy/static/provider/kind" "./deploy/static/provider/exoscale" "./deploy/static/provider/cloud" "./deploy/static/provider/scw" "./deploy/static/provider/aws" "./deploy/static/provider/aws/nlb-with-tls-termination/")

mkdir -p diffs
for dir in "${MANIFESTS[@]}"
do
  kustomize build $dir/ > diffs/$(basename $dir).yaml
done
EOF

chmod +x diffmaker.sh
./diffmaker.sh

ga diffmaker.sh
ga diffs # save the original manifests
gcm 'original manifests'

# checkout new manifests and generate
git reset 2022-01-04-static-manifest-generation -- deploy/static
git checkout 2022-01-04-static-manifest-generation -- deploy/static
./hack/generate-deploy-scripts.sh

# save the new manifests and push to my fork
ga diffs
gcm 'PR #8099 manifests'
gpsup

git rev-parse --short HEAD

resulting diff - there isn't one

ga diffs
gcm 'PR #8099 manifests'
>> nothing added to commit but untracked files present (use "git add" to track)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• n/a I have added tests to cover my changes.
• All new and existing tests passed.

[k8s-ci-robot]

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[afirth]

/hold either this or #8000 should be merged but not both

@rikatz this contains only the existing reordered manifests and the script changes. There are two comments in hack/generate-deploy-scripts.sh which when reverted will generate all the manifests as in #8000. As indicated in "How has this been tested" I think a script is the best way to verify the lack of manifest diffs besides the reordering. I've run it again for this manifest

[afirth]

rebased again. I will close #8000 as it doesn't make sense to keep both of them up to date with the rebases. After this is in it's trivial to generate for the other versions
/assign @rikatz

[rikatz]

/approve
/lgtm
/hold

Also @afirth please rebase and let me know (as the lgtm will be removed)
@strongjz @ElvinEfendi one last look here please :)

Thanks!

[afirth]

@rikatz rebased
(just release.md)
will teach me to clean up formatting in the future :/

[rikatz]

/lgtm
/approve
Thanks!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: afirth, rikatz

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[rikatz]

/hold cancel