add plugins to the key components section of the faq

during a recent discussion on discord it was not clear to some folks the conceptual difference between clients and plugins. this just adds a bit more high level info up top on the FAQ for future creators.

docs/docs/faq.md

@@ -28,6 +28,7 @@ Eliza's architecture consists of several interconnected components:
 - **Agents**: These are the core elements that represent individual AI personalities. Agents operate within a runtime environment and interact with various platforms.
 - **Actions**: Actions are predefined behaviors that agents can execute in response to messages, enabling them to perform tasks and interact with external systems.
 - **Clients**: Clients act as interfaces between agents and specific platforms, such as Discord, Twitter, and Telegram. They handle platform-specific message formats and communication protocols.
+- **Plugins**: Plugins are modular way to extend the core functionality with additional features, actions, evaluators, and providers. They are self-contained modules that can be easily added or removed to customize your agent's capabilities
 - **Providers**: Providers supply agents with contextual information, including time awareness, user relationships, and data from external sources.
 - **Evaluators**: These modules assess and extract information from conversations, helping agents track goals, build memory, and maintain context awareness.
 - **Character Files**: These JSON files define the personality, knowledge, and behavior of each AI agent.