Convert procedural hooks to object oriented hooks

I tried converting User related hooks as the first step, and all went smoothly.

I have converted hooks to the new object oriented style.

The only functions remaining in the .module file are the template preprocess functions. Not sure if it's possible to replace them and remove the .module file altogether.

I also updated tests making direct calls to hook functions.

All tests are passing, and I've carried out some manual testing. Not sure if there are any gaps in our test coverage. I'm sure my manual tests didn't cover all the functionality provided by the hooks.

Appreciate if anyone can review.

bluegeek9 → changed the visibility of the branch 1.0.x to hidden.