Add checkDocumentIsReady helper function

Problem/Motivation

Helpers functions are Javascript functions you can use anywhere in the theme.
It's a very good concept to be in vartheme_bs5.

Sometimes you have to check if the document is ready and loaded or not before doing work,
because of that, checkDocumentIsReady helper will make this check.

Proposed resolution

• Add a new directory called helpers under src directory.
• Add checkDocumentIsReady.js file contains checkDocumentIsReady helper function.
• Add index.js file to export all helpers to allow call all helpers anywhere in the same way.

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
• ➖ 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-alpha1 → , vartheme_bs5-2.0.0-alpha1 →

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 #3303461 → by Abdullah Yassin → : Added checkDocumentIsReady helper function