Feature/media cwt module

[sverekar]

Edge worker compatible CWT module.

Limitations

• Currently the module only support API's for verification of CWT tokens that are generated using HS256 algorithm only.
• Currently the module only support MAC0 COSE message structure. Refer this page for more details on CBOR Object Signing and Encryption (COSE).
• As of now, EW do not support KMI to manage verification keys, hence these keys are fetched from property manager user defined variable which might not be a secure way. More details on user defined variables can be found here

Note: As of now only HS256 algo is supported for CWT module due to time constraint and requirement of the same in watermarking module. In future release we can plan to support other necessary algorithms. supporting other algorithms requires understanding on COSE message structure for public key cryptography. Refer this page for more details on CBOR Object Signing and Encryption (COSE).

Dependencies/Todo

• [ ] Add documentation page link. (https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/akamai-edgeworkers/index.d.ts)