Add Imagor image provider support

[stefashkaa]

Feature Title

Add Imagor image provider support

Description

Add an Imagor provider profile that shares the Thumbor URL serializer proposed in “Add Thumbor image provider support” #31 . Imagor explicitly adopts Thumbor-style URL syntax.

Use Case

An application running Imagor needs responsive variants through the shared image API with options that match its deployed server’s filters and signing configuration.

Proposed Solution

• Add and export imagor through the core provider registry so Angular, React, and Svelte can use the shared configuration.
• Complete the Thumbor serializer first, then add an Imagor profile or thin wrapper for its supported geometry, filters, and endpoint configuration.
• Validate filters and signing against Imagor’s own documentation and examples rather than treating all Thumbor extensions as interchangeable.
• Keep shared path construction in one implementation. Generate signatures after transformations with secrets kept on the server, and allow unsigned URLs only when explicitly configured for a compatible deployment.
• Add setup documentation and focused fixtures covering Imagor URL fixtures, supported filters, signing, unsafe configuration, and shared Thumbor serialization. Validate advertised dimensions and content types against an enabled service or controlled server where applicable.

Alternatives Considered

Use the proposed Thumbor provider with a verified compatible subset or generate Imagor URLs directly. A separate profile would make Imagor-specific limits and configuration explicit.

Examples from Other Libraries

• Not found
• Source repository, Thumbor compatibility, and transformation examples