feat: Content Block publish component generator

[istarkov]

Description

1 commit = fixtures
2nd commit = code changes
3rd = size changes

ref #3994

Publish result:
https://webstudio-fixture-project-a-0su3o.wstd.work/content-block

See fixtures for generated code.

Steps for reproduction

1. click button
2. expect xyz

Code Review

• hi @kof, I need you to do
  • conceptual review (architecture, feature-correctness)
  • detailed review (read every line)
  • test it on preview

Before requesting a review

• made a self-review
• added inline comments where things may be not obvious (the "why", not "what")

Before merging

• tested locally and on preview environment (preview dev login: 0000)
• updated test cases document
• added tests
• if any new env variables are added, added them to .env file

[TrySound]

A would add a couple basic tests to easier find the expected result

[istarkov]

Tests added