Multi agent orchestration ADR (microsoft#11579)

### Motivation and Context

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Multi-agent orchestration ADR. Includes the following orchestrations:
- Concurrent
- Sequential
- Group Chat
- Magentic One
- Handoff

### Description

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An ADR for multi-agent orchestration in Semantic Kernel.

.Net PR: microsoft#11542
Python PR: microsoft#11993

### Contribution Checklist

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- [x] The code builds clean without any errors or warnings
- [x] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄

Author: TaoChenOSU

.github/_typos.toml

@@ -44,6 +44,7 @@ dall = "dall"             # OpenAI model name
 pn = "pn"                 # Kiota parameter
 nin = "nin"               # MongoDB "not in" operator
 asend = "asend"           # Async generator method
+Magentic = "Magentic"     # Magentic is a name of an agentic pattern
 
 [default.extend-identifiers]
 ags = "ags" # Azure Graph Service