Hi,
Thank you for all your help.
I had taken a break on this project for a while.
Now I am resuming it.
I have now installed piwigo.org on photos.lagubandhu.com
I uploaded 2 sample albums.
I can see that the keywords also got uploaded.
The issue remains with the keyword tree.
Although Tag Groups extension will create a 2-level hierarchy, I will have to redefine all tags in the format {country:India} whereas currently 'Country' and 'India' are 2 different tags at 2 different levels.

How to export this tag or keyword tree from Digikam?
Once I am able to upload the tag structure from Digikam, then I will take this project to the next level by moving the entire file collection and tag database to the cloud.

Please help me.