Ogc Api - Styles

[lexxamcode]

Resolves #31
This Pull Request adds support for the OGC API - Styles standard.

A library has been written that contains an object model for working with styles and style metadata, as well as controllers that can be integrated into an existing ASP.NET application.

New Endpoints:

• GET /{collectionId}/styles returns styles associated with the collection

• POST /{collectionId}/styles adds new style (or new stylesheet of the style) for the collection

• PATCH /{collectionId}/styles updates default style for the associated collection

• GET /{collectionId}/styles/{styleId} returns style info or stylesheet of the style if format is specified

• PUT /{collectionId}/styles/{styleId} replaces existing stylesheet of the style

• DELETE /{collectionId}/styles/{styleId} deletes style of the collection

• GET /{collectionId}/styles/{styleId}/metadata returns metadata of the style

• PUT /{collectionId}/styles/{styleId}/metadata replaces metadata of the style

• PATCH /{collectionId}/styles/{styleId}/metadata updates metadata of the style

By default, styles are stored in the server's file system.
To change the way styles are stored, you need to implement IStyleStorage and IMetadataStorage.

[alxmcs]

nit: I would suggest adding summaries to public methods and classes.

[danlla]

Before merging:

1. Add a new markdown file documenting the feature (e.g., docs/styles.md) and link it in docs/index.md.
2. Include the new package in docs/installation.md.
3. Add the new standard to the table in docs/overview.md.
4. Update .github/workflows/publish-packages.yml to build and publish the new package.

[kolyanch]

The new controllers currently do not have any authorization. At least for style modification methods, they are necessary, otherwise the API will be susceptible to attacks.