As an AntTP user
I want to be able to provide some encrypted data and return decrypted data
So that I can use my app private key to decrypt the data that has been shared with me

Given crypto_controller.rs already exists and provides encrypt endpoint
When adding decrypet support
Then use the encrypt endpoint/function as an example
And create a new decrypt endpoint at /anttp-0/crypto/decrypt
And request must use the same CryptoContent request body
And with the encrypted data being provided as the map key (like encrypt endpoint)
And response must also have the 'CryptoContent' body type
And both the data key in the request and the response content must be base64 
And the payload must look similar to the below:

```
{
  [
    "base64_encrypted_data_1" : {
      "content": "base64_decrypted_data_1"
    },
    "base64_encrypted_data_2" : {
      "content": "base64_decrypted_data_2"
    },
    ...
    "base64_encrypted_data_N" : {
      "content": "base64_decrypted_data_N"
    },
  ]
}
```

Given crypto_service.rs already exists and provides an encrypt function
When adding decrypt support
Then add decrypt and decrypt_map functions, using encrypt/encrypt_map (but don't use public_key) and sign/sign_map as examples
And use base64 decode to extract the data key value
And use the app_private_key (from anttp_config.rs) to decrypt the data using private_key.decrypt() (instead of encrypting)
And then return the data_map with the 'content' CryptoContent field populated with the result
And use private_key.decrypt() to get the raw bytes (from decrypt function), then use base64 encode to safely place the decrypted data in the data_map 'content' variable (in decrypt_map function)

Given /src/lib.rs will need to be updated with the new endpoints and route
When adding the new controller endpoint
Then update lib.rs to add /anttp-0/crypto/decrypt like /anttp-0/crypto/encrypt/{public_key}

Implementation Notes

- Place any unit tests at the bottom of the same file as the associated production code
- Increment patch version of anttp package in Cargo.toml
- Create a copy of this issue description and save to /spec using the name of this issue as the filename (with lower underscore case, starting with the 5 char padded issue number, e.g. 00001_issue_title.txt)
- Update unit tests to validate the changes
- Update newman tests to include the new endpoint