Move the Alert component back from Atoms to Molecules in Storybook and update Varbase Docs

Problem/Motivation

Following with the Varbase Design System

Proposed resolution

• Move the Alert component from Molecules to Atoms in Storybook
• Update Varbase Docs for Customize a Varbase Single Directory Components (SDC) In a Custom Theme
• Copy the Varbase Component to the Custom theme

Remaining tasks

• ✅ File an issue about this project
• ✅ Addition/Change/Update/Fix to this project
• ✅ Testing to ensure no regression
• ➖ Automated unit/functional testing coverage
• ➖ Developer Documentation support on feature change/addition
• ➖ User Guide Documentation support on feature change/addition
• ➖ UX/UI designer responsibilities
• ➖ Accessibility and Readability
• ✅ Code review from 1 Varbase core team member
• ✅ Full testing and approval
• ✅ Credit contributors
• ✅ Review with the product owner
• ✅ Update Release Notes and Update Helper on new feature change/addition
• ✅ Release varbase-10.0.0-rc2, varbase_components-2.0.0-beta3

Varbase update type

• ✅ No Update
• ➖ Optional Update
• ➖ Forced Update
• ➖ Forced Update if Unchanged

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• Issue #3419232: Moved the Alert component back from Atoms to Molecules in Storybook and update Varbase Docs