docs: Add Aviationstack MCP

[Pradumnasaraf]

Description

Adding Aviationstack MCP server to the community servers list in README.md.

Server Details

Server: Aviationstack (new entry)
Changes to: Community servers documentation section

Motivation and Context

This update adds the MCP server https://github.com/Pradumnasaraf/aviationstack-mcp to the list of community servers, making it easier for users to find and use.

How Has This Been Tested?

• Querying experiments and runs
• Running tests.

Breaking Changes

No

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Protocol Documentation
• My changes follows MCP security best practices
• I have updated the server's README accordingly
• I have tested this with an LLM client
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have documented all environment variables and configuration options

Additional context

[Pradumnasaraf]

Hey @olaservo, In case you missed the ping!