Move not public parts of the k6 API in internal package

[mstoykov]

What?

Move a lot of k6 code under internal .

This is done through some scripts that are also committed and will be removed after the final move.

Why?

Define k6 public API by moving everything else in internal.

This is hopefully the first in multiple steps. This is the one that is the most brutforce and moves the most amount of code around.

Checklist

• I have performed a self-review of my code.
• I have added tests for my changes.
• I have run linter locally (make lint) and all checks pass.
• I have run tests locally (make tests) and all tests pass.
• I have commented on my code, particularly in hard-to-understand areas.

Related PR(s)/Issue(s)

[mstoykov]

Please, any reviewer run the internalize.sh script locally after checking out the first commmit and see if it makes the same changes.

[codebien]

git restore -s master -- ./
./internalize.sh
git status

Untracked files:
  (use "git add <file>..." to include in what will be committed)
	cloudapi/insights/
	js/modules/k6/browser/
	js/modules/k6/experimental/
	js/summary-wrapper.js
	js/summary.js
	js/tc39/
	lib/testutils/
	output/cloud/expv2/integration/
	output/cloud/expv2/pbcloud/
	vendor/github.com/grafana/xk6-dashboard/dashboard/testdata/
	vendor/github.com/grafana/xk6-webcrypto/
	vendor/github.com/grafana/xk6-websockets/
	vendor/go.opentelemetry.io/otel/sdk/metric/internal/exemplar/
	vendor/go.opentelemetry.io/otel/verify_examples.sh
	vendor/google.golang.org/protobuf/internal/errors/is_go112.go
	vendor/google.golang.org/protobuf/internal/errors/is_go113.go

Instead, I would expect an empty list here. Is it expected? 🤔 The reason should be a different starting point of master.

[codebien]

@mstoykov We should also consider to lock master to prevent to rebase all the time. Can you rebase the last time and lock it, please?

https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/managing-protected-branches/about-protected-branches#lock-branch

[mstoykov]

@codebien can you try again, please. Yeah unfortunately making changes to master makes this constantly move. And we did merge a bunch of stuff yesterday after I finally managed to get most of the final things doen.

On locking master - I kind of prefer that I do not block everyone from being able to merge stuff, given this takes me 2-5 minutes to rebase.

[codebien]

git fetch origin
git reset --hard origin/internalize
git switch master
git pull --rebase origin master
git switch internalize
git restore -s master -- ./
git restore internalize.patch internalize.sh publicly_used_imports.txt
./internalize.sh

Untracked files:
  (use "git add <file>..." to include in what will be committed)
	cloudapi/insights/
	js/modules/k6/browser/
	js/modules/k6/experimental/
	js/modules/k6/webcrypto/
	js/summary-wrapper.js
	js/summary.js
	js/tc39/
	lib/testutils/
	output/cloud/expv2/integration/
	output/cloud/expv2/pbcloud/