Add More Elasticsearch Authentication Type

[MikeAlhayek]

This pull request introduces expanded authentication and environment support for Elasticsearch data sources, along with related updates to infrastructure abstractions, documentation, and Azure AI Search integration. The main focus is on enabling Elastic Cloud deployments and supporting multiple authentication modes, while also simplifying localization handling in index profile descriptors.

Elasticsearch Data Source Enhancements:

• Added support for Elastic Cloud deployments with a new CloudId property and explicit EnvironmentType selection (SelfManaged or CloudHosted). The environment is now inferred or normalized via a helper method. [1] [2] [3]
• Introduced new authentication modes: ApiKey, Base64ApiKey, and KeyIdAndKey, with corresponding protected properties (ApiKey, Base64ApiKey, ApiKeyId). The authentication type is now normalized based on provided credentials. [1] [2]
• Updated documentation to describe all new properties, supported authentication types, and environment selection, including guidance for both self-managed and Elastic Cloud scenarios. [1] [2] [3] [4] [5] [6]
• Added release notes summarizing the expanded authentication and environment support.

Infrastructure and Localization Simplification:

• Changed IndexProfileSourceDescriptor to use plain string for ProviderDisplayName, DisplayName, and Description instead of LocalizedString, and removed the unnecessary Microsoft.Extensions.Localization import. [1] [2]
• Updated IndexProfileSourceOptions to match the new string-based properties and added an overload for AddOrUpdate accepting a string display name. [1] [2]
• Updated Azure AI Search source registration to set DisplayName and Description as plain strings. [1] [2] [3]