Add topic detection feature

[michaeljolley]

Proposed changes

• Support calling our Topic Detection Feature with Go SDK.
• Developers can utilize Topic Detection feature with detect_topics=true query parameter
• Update any usage requests that allow filtering by feature to include detect_topics

Context

Allow customers to identify and detect topics in their transcript.

Other information

• Sample URL - https://api.beta.deepgram.com/v1/listen?detect_topics=true
  • Engineering Doc - detect_topics: string indicating which version of the topic detection model to use. Setting this variable turns topic detection on.

Sample Output

topics: An optional array of the topics recognized in the audio. The array will be sorted by the start_word attribute, ascending.

[briancbarrow]

closed with #29