Adjust user_status icons to a more fine- grained solution

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Is your feature request related to a problem? Please describe.
Follow up to https://github.com/nextcloud/server/pull/40615

Describe the solution you'd like
The current user status options could be more fine- grained, especially with the introduction of the automated user status

Describe alternatives you've considered
Leaving the user status as is.

Additional context
@nimishavijay said:

Would be nice if that could be a DND icon but in yellow maybe?

I love the idea of using yellow for a busy state! We will also have to indicate it with icon/shape in addition to color, because would be difficult to distinguish between the DND and busy state for people with colorblindness:

No color blindness

Green-blind

Red-blind

How about using an icon that is similar to DND -- a focus icon. iOS has a crescent moon (like the Away status in NC) but Android had a target-looking icon in a previous version

We could use something reminiscent of a focus mode like that? What do you think? (icons used here are radiobox-marked, circle-slice-8, record-circle, and circle-double)

My vote would go for 1 or 3, what do you think? also @jancborchardt @marcoambrosini @szaimen

@jancborchardt said:

@miaulalala regarding which calendars to take into account, I would say starting out with "Personal" and then any event which you are participant of in other calendars would be best. The second part might need work in other areas though?

About the state:

Microsoft Teams uses a filled red circle – similar to do not disturb but also reminiscing "recording in progress".
To distinguish it from the "Available" green circle, we can add a checkmark to the green circle. So we could align with Microsoft Teams to use a de-facto standard. It would also include adjusting the "Away" state from a crescent moon into a clock.
Also note they have an interesting "Out of office" state on the bottom. :)

(There might be possible conflict with the desktop client sync icon which can also be a white checkmark in a green circle. However this is also a more general symbol used elsewhere like we will also use in our admin overview that will come with 28 as well.)

https://learn.microsoft.com/en-us/microsoftteams/presence-admins

Start with the follow-up to PR 40615 and review the current user-status options described in this issue. Compare the proposed states and accessibility concerns; done means agreeing on and implementing a fine-grained icon and shape system that distinguishes statuses without relying on color alone.