docs: merge Alibaba install guide into quick install guide

[yoyo-go]

According to the slack thread with @joestringer , we diecide to merge the Alibaba ACK install guide into the Cilium quick install guide, as a new tab named Alibaba ACK.

@qmonnet @lizrice @xmulligan Please let me know if you have any comment on it.

[qmonnet]

Looks good, thank you!

Two minor suggestions below.

[christarazi]

LGTM pending Quentin's suggestions.

[yoyo-go]

Hi @qmonnet Sorry for the late cause I am sick for a week, I have updated this PR per your comments, But @joestringer suggests us to merge the Alibaba one into the Installation using Helm page. How do you think about this idea?

[qmonnet]

@yoyo-go Can you please provide some context, what's the motivation? I suppose you refer to this discussion and that this is because Alibaba does not support install through the Cilium CLI? In that case, yes, it's probably better to move it to the Helm page instead.

[yoyo-go]

@qmonnet Yes that is the discussion, and I have updated the Helm page, and add a ref in our quick installation guide. Please have a look and let me know if this PR is ready.

[qmonnet]

Thanks! But wasn't Joe's comment about adding the instructions to the Helm page only?
Cc @joestringer can you please have a quick look?

[joestringer]

@qmonnet What's the question?

At a glance, the changes look roughly right:

• ACK is now listed under the helm install
• There is a section for ACK under the cilium install. Ideally this would just say to install via cilium CLI, but I guess we have not validated that this works so it's fine by me that it says to use the helm install approach instead.
• Remove the cloud install page because the current version implies that we don't support other clouds. (The alternatives here are either list every cloud there, or remove the page. I'm OK with removing the page like is done here)

[qmonnet]

Apologies, I got confused when reviewing the PR earlier today and thought we were adding the instructions both to the Helm page and the Quick install guide (where we in fact redirect to the Helm page). Sorry for the noise and thanks for taking a look.

All good then, let's get this merged! Just waiting for the Travis build just in case.