Update ld schema to support multikey and wytchspace implementations

[humrochagf]

After watching the latest json-ld canonicalize exceptions the most common are coming from instances that implement those two contexts (Both are failing due to bad redirection):

• https://w3id.org/security/multikey/v1
• https://purl.org/wytchspace/ns/ap/1.0

For the first one, I'm fixing it by bringing the entire context to the schema since it's relatively small and is more commonly used.

For the second one, I just added the proper redirection inside the context since it's less common and bringing the entire context is less valuable.

[andrewgodwin]

Lovely, thank you!

[osmaa]

what benefit are we getting from building in that wytchspace AP context?

[andrewgodwin]

Overcoming parsing issues before we fix them as we were discussing them on #644, I'd say!