Add a label for WG future meetings calendar icon

[kesara]

Description

At the moment there's only an icon with a tool tip which might be hard to find. Adding a label to tell users about the .ics link to future meetings might be better.

Code of Conduct

• [X] I agree to follow the IETF's Code of Conduct

[rjsparks]

Remove the icon and add buttons like what appear at meeting/upcoming?

[kesara]

@rjsparks that seems better to me.

[tgeoghegan]

I was able to get the WG-specific calendar I wanted by:

• going to https://datatracker.ietf.org/meeting/upcoming
• using "customize the meeting list" to narrow it down to my WG of interest (e.g. https://datatracker.ietf.org/meeting/upcoming?show=yourwghere)
• importing the "subscribe with webcal" link into my calendar client

...but to echo rjsparks' suggestion above, it'd be nice if each WG meetings page had a customized meeting list link prominently placed, as WG members have a habit of forgetting about interim meetings and sometimes ask for a calendar just like this.