Add group call sample

[NT-D]

Why

Through the CSE code-with engagement, we've learned developers want to know how to implement following scenario. So, I've implemented code sample for sharing learning.

• Start group call with specific users by specifying email addresses
• Join existing online meeting by event id
• Start group call if the existing meeting doesn't have online meeting setting

What

Implement 3 scenarios above

[NT-D]

@zihzhan , @yizhenww Any chance to be reviewed by you ?

[zihzhan-msft]

Hi,
Can you please move this Start Group Sample under Public Folder and use sample_readme_template.md as a template for your Sample README.md file?

[NT-D]

Sure, let me update my PR. I'll send next PR by next week.

[NT-D]

@zihzhan Hi, I've move sample under public folder and updated Readme based on the template. Would you please review PR ?

[1fabi0]

ok I just partial reviewed it so I see you have their some todos left in your comments you want to do also I want to ask you if you please always use IConfiguration and not Enviroment because then it's possible to define some things in a .json-File and also use the Enviroment Variables. Also as I see you use azure functions to host this, not seen this yet, but is it there possible to do local media like a compliance recording or something like the Huebot.
If you have any questions or need some help feel free to ask me. But it looks very good.