Add Video API

[superchilled]

This PR implements the Vonage Video API in the SDK. Specifically it adds the following Video API functionality:

• Session creation
• Client token generation
• Live streaming broadcasts
• Archive recordings
• Stream management
• Moderation
• Signalling
• SIP

[codecov-commenter]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (d4d2317) 97.97% compared to head (a09d17c) 98.05%.

:exclamation: Current head a09d17c differs from pull request most recent head 0dc6c1e. Consider uploading reports for the commit 0dc6c1e to get more accurate results

Files	Patch %	Lines
lib/vonage/client.rb	66.66%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #297 +/- ## ========================================== + Coverage 97.97% 98.05% +0.08% ========================================== Files 109 119 +10 Lines 2020 2162 +142 ========================================== + Hits 1979 2120 +141 - Misses 41 42 +1 ```

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