rtmp-services: Add Streamvi service

[Be1erafon]

Description

Added Streamvi to streaming services drop down.

Motivation and Context

Popular restreaming service

Types of changes

New feature (non-breaking change which adds functionality)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[Fenrirthviti]

Please provide confirmation/proof that you are an official representative of Steamvi.

[Be1erafon]

Please provide confirmation/proof that you are an official representative of Steamvi.

I added my account in TXT, is that enough?
dig txt obs.streamvi.io (Following the example from the previously added service)

[Be1erafon]

By the way, it would be convenient to add a check for, TXT directly to services.json, there will be no such questions