Minimize use of argoproj/pkg

[crenshaw-dev]

Summary

We currently rely on argoproj/pkg for some relatively trivial utilities. I believe the original idea behind the package was to share common utilities among the argoproj suite. In practice, I think the uses of pkg by the 4 main Argo projects are fairly disjoint.

Motivation

1. Bumping versions is a pain
2. Maintaining a separate repo means separate issues/PRs/dependabot/etc.
3. One has to avoid introducing breaking changes to functions that probably aren't even shared

Proposal

We should minimize Argo CD's use of pkg. For whatever utilities remain that are actually shared by all or most Argo projects should be extracted into their own purpose-specific modules with their own documentation and minimal dependencies. Ideally these modules would be treated as their own micro-projects (think similar to the logrus bridge), ideally useful to the broader ecosystem instead of just Argo.

Uses by the top 4 projects:

Command:

grep -r -h '"github.com/argoproj/pkg' **.go | sed 's/^[^"]*"//' | sed 's/"$//' | sort | uniq

Argo CD

github.com/argoproj/pkg/exec
github.com/argoproj/pkg/grpc/http
github.com/argoproj/pkg/kubeclientmetrics
github.com/argoproj/pkg/stats
github.com/argoproj/pkg/sync
github.com/argoproj/pkg/time

The exec module is apparently unique to Argo CD and should probably just be moved to the argo-cd repo.

Argo Events

github.com/argoproj/pkg/expr

Argo Rollouts

github.com/argoproj/pkg/grpc/http
github.com/argoproj/pkg/kubeclientmetrics

Argo Workflows

github.com/argoproj/pkg/cli
github.com/argoproj/pkg/errors
github.com/argoproj/pkg/file
github.com/argoproj/pkg/grpc/http
github.com/argoproj/pkg/humanize
github.com/argoproj/pkg/json
github.com/argoproj/pkg/kube/cli
github.com/argoproj/pkg/kube/errors
github.com/argoproj/pkg/rand
github.com/argoproj/pkg/s3
github.com/argoproj/pkg/stats
github.com/argoproj/pkg/strftime
github.com/argoproj/pkg/sync
github.com/argoproj/pkg/time

The following appear to be completely unique to argo-workflows and should probably just be reincorporated to that repo:

github.com/argoproj/pkg/cli
github.com/argoproj/pkg/file
github.com/argoproj/pkg/json
github.com/argoproj/pkg/kube/cli
github.com/argoproj/pkg/kube/errors
github.com/argoproj/pkg/s3
github.com/argoproj/pkg/strftime