Add the `site` value to ContentPathType

[anatol-sialitski]

https://github.com/enonic/lib-guillotine/issues/192#issuecomment-983521723 Add the site value to ContentPathType.

After that ContentPathType supports two options:

• siteRelative returns the relative path without initial '/' i.e. my-content/path
• site returns same response but with initial '/' i.e. /my-content/path

[rymsha]

I have written my concerns about "site" ConttentPathType here

All graphql client libraries support schema transformation. So there is no need to complicate our API with trivial transformations

[sigdestad]

Is schema Transformation equivalent to data Transformation?

[rymsha]

Yes:

Other use cases for a read function include:

• Transforming cached data to suit your client's needs, such as rounding floating-point values to the nearest integer
• Deriving local-only fields from one or more schema fields on the same object (such as deriving an age field from a birthDate field)
• Deriving local-only fields from one or more schema fields across multiple objects

[sigdestad]

Beautiful.

[anatol-sialitski]

Maybe in this case we can get rid of the type argument in the _path field?

[rymsha]

I'd keep some room for improvement, if we already have it. Just in case.