Move src/lib/* to src

[arelra]

What does this change?

We currently have the following directory structure:

- src
  - core (lib type modules for export)
  - lib (containing most of the codebase)
    - dfp
    - messenger
    - ...

This PR updates the structure to the following:

- src
  - core (lib type modules for export)
  - dfp
  - messenger
  - ...

I've checked the build output and it is exactly the same.

Why?

The current structure is a hangover from:

1. the migration of the commercial code from frontend to this repo commercial
2. the merging of commercial-core into commercial

Having all directories flattened under src/ is more standard.

The directory structure however is still largely carried over from Frontend which we can improve but this is the first step.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 912f3e3

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[chrislomaxjones]

This is a great improvement! Can't say I reviewed every file, but if all the checks have passed...