Add Samples and Demos list on DCE docs

[Felix-Dynamsoft]

We should have a samples and demos list on the docs.

This should also be maintained the same way for DCE samples (also related: Dynamsoft/camera-enhancer-javascript-samples#16)

See DBR samples and Demos: https://www.dynamsoft.com/barcode-reader/docs/web/programming/javascript/samples-demos/index.html

Can we also have a list of the version that it's currently using for the samples?

[Tom-Dynamsoft]

On Hold -> to consider when merging all documentation into one