perf: refactor @codeimage/theme with chunk splitting

[riccardoperra]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/riccardoperra/codeimage/blob/main/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: #264

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[X] No

Other information

[changeset-bot]

🦋 Changeset detected

Latest commit: 0c81480

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
@codeimage/config	Patch
@codeimage/highlight	Patch
@codeimage/app	Patch

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Name	Status	Preview	Updated
codeimage	✅ Ready (Inspect)	Visit Preview	Jun 11, 2022 at 2:19PM (UTC)