[NET-9839] fix: add shared version submodule

[zalimeni]

Introduce a new submodule for sharing versioning code across the binary-producing submodules in consul-k8s repo.

This is both an improvement in terms of consolidation, as well as a fix for incorrect control-plane submodule pinning in the control-plane/cni submodule that led to incorrect dev versions being used in 1.4.2 and 1.4.3 (the first releases that included a valid version of control-plane/cni. See #4054 comments for more context.

I have a separate change (#4093) to move us to using an embedded VERSION plaintext file like consul, but splitting that out from this change for brevity and to reduce risk before the upcoming release. The follow-up is lower priority and may not be worth pushing through soon, but would be a nice simplification.

Once merged, I plan to manually backport this change to .x branches and release/1.5.0, modifying the versions as needed.

Changes proposed in this PR

• Consolidate version management in consul-k8s binaries into a single shared (private) submodule
• Fix a bug in prepare- scripts leaving chart version blank when version is non-dev
• Unrelated cleanup in go.mod/go.sum due to running go mod tidy after module swaps

How I've tested this PR

control-plane Docker in CI:

• https://github.com/hashicorp/consul-k8s/actions/runs/9421065328/job/25954781084#step:6:10 1.6.0-dev
• https://github.com/hashicorp/consul-k8s/actions/runs/9421065328/job/25954781381#step:7:10 1.6.0-dev+fips1402

Downloaded from CI run above:

~/Downloads/consul-k8s_1.6.0-dev_linux_amd64 
❯ docker run -it --rm --platform linux/amd64 -v "$(pwd):/home/test" -w "/home/test" ubuntu ./consul-k8s -version
v1.6.0-dev (cf59978+CHANGES)

~/Downloads/consul-cni_1.6.0-dev_linux_amd64   
❯ docker run -it --rm --platform linux/amd64 -v "$(pwd):/home/test" -w "/home/test" ubuntu ./consul-cni -version
CNI consul-cni plugin v1.6.0-dev (cf59978+CHANGES)
CNI protocol versions supported: 0.1.0, 0.2.0, 0.3.0, 0.3.1, 0.4.0, 1.0.0

Local:

❯ make version
1.6.0-dev

❯ cd control-plane/
~/workspace/consul-k8s/control-plane 
❯ go run . -version
v1.6.0-dev

❯ cd cni
~/workspace/consul-k8s/control-plane/cni 
❯ go run . -version
CNI consul-cni plugin v1.6.0-dev
CNI protocol versions supported: 0.1.0, 0.2.0, 0.3.0, 0.3.1, 0.4.0, 1.0.0

❯ cd ../../cli
~/workspace/consul-k8s/cli
❯ go run . -version
v1.6.0-dev

~/workspace/consul-k8s 
❯ make prepare-release
prepare_release: dir:/Users/michael.zalimeni/workspace/consul-k8s consul-k8s:1.999.1 consul:1.19.0 consul-dataplane:1.999.1 date:February 27, 2080 git tag:v1.4.3
==> Updating version/version.go with version info: 1.999.1
==> Updating Helm chart version, consul-k8s: 1.999.1  consul: 1.19.0  consul-dataplane: 1.999.1
Checking charts for hashicorpreview images. . .
Charts do not contain hashicorpreview images, ready for release!

❯ git status
On branch zalimeni/shared-version-cli-control-plane-cni
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
	modified:   ../CHANGELOG.md
	modified:   ../charts/consul/Chart.yaml
	modified:   ../charts/consul/values.yaml
	modified:   ../version/version.go

❯ make version
1.999.1

❯ cd control-plane/
~/workspace/consul-k8s/control-plane !4  
❯ go run . -version
v1.999.1-dev

❯ cd cni
~/workspace/consul-k8s/control-plane/cni !4  
❯ go run . -version
CNI consul-cni plugin v1.999.1-dev
CNI protocol versions supported: 0.1.0, 0.2.0, 0.3.0, 0.3.1, 0.4.0, 1.0.0

❯ cd ../../cli
~/workspace/consul-k8s/cli !4
❯ go run . -version
v1.999.1-dev

## Emulate build steps in build.yml to remove dev marker
❯ export GIT_COMMIT=$(git rev-parse --short HEAD)
export GIT_DIRTY=$(test -n "$(git status --porcelain)" && echo "+CHANGES")
export GIT_IMPORT=github.com/hashicorp/consul-k8s/version
export GOLDFLAGS="-X ${GIT_IMPORT}.GitCommit=${GIT_COMMIT}${GIT_DIRTY} -X ${GIT_IMPORT}.GitDescribe=1.999.1"

❯ cd control-plane/
~/workspace/consul-k8s/control-plane !1   
❯ go run -ldflags "${GOLDFLAGS}" . -version
v1.999.1

❯ cd cni
~/workspace/consul-k8s/control-plane/cni !1 
❯ go run -ldflags "${GOLDFLAGS}" . -version
CNI consul-cni plugin v1.999.1
CNI protocol versions supported: 0.1.0, 0.2.0, 0.3.0, 0.3.1, 0.4.0, 1.0.0

❯ cd ../../cli
~/workspace/consul-k8s/cli !1
❯ go run -ldflags "${GOLDFLAGS}" . -version
v1.999.1

How I expect reviewers to test this PR

👀 + 🧠

Checklist

• Tests added
• CHANGELOG entry added

[zalimeni]

make prepare-release test:

[DanStough]

👍 Thank you for the fix!