Improve the main models table and example/tutorials in README

[lgabs]

• Fixes [ASK] Is there a way to find all GPU supported models?  #609 (specifying CPU/GPU supported for each of the models).
• Adding more links to existing examples and tutorials for the models. I think this table is where most users refer to when looking for model details. Therefore, having these links will raise visibility.

[tqtg]

Hey @lgabs, thanks a lot for making this changes. It will be very helpful for model references. I'm just trying to merge environment and requirement into one column to save some space when displaying the whole table in the main page.

[lgabs]

Thanks! Yeah, it will be better to save some space. I can do it too, if you didn't start this change yet.

[tqtg]

Let me try to propose some changes first and see if you're good with that.

[lgabs]

Nice, i'm good with that change, it's cleaner now.

[tqtg]

@lgabs sorry for introducing other changes to this PR. However, I think it's a good chance to have more example/tutorial links added to the main table for users reference.

[tqtg]

tagging other key contributors to seek for better ideas @darrylong @lthoang @hieuddo @saghiles

[darrylong]

I agree to these changes, it's okay so long as it is readable to users.

Anyway, non-related but i'm exploring an idea to add this table to our readthedocs documentation site with a filter/sort function. This will be explored in another PR.