Create an endpoint to encrypt data with a public key

As an AntTP user
I want to be able to provide some data and a public key and have the encrypted data returned
So that I can store sensitive data safely for the associated private key holder

Given crypto_controller.rs already exists and provides sign/verify endpoints
When adding encrypt support
Then use the verify endpoint/function as an example
And create a new encrypt endpoint at /anttp-0/crypto/encrypt/{public_key}
And request must include a similar body type to 'Crypto' struct but instead 'CryptoContent'
And with 'data' being provided as the map key (like verify), but it must be base64 encoded (as maybe binary data)
And response must also have the 'CryptoContent' body type, with the content base64 encoded too
And the payload must look similar to the below:

```
{
  [
    "base64_data_1" : {
      "content": "base64_encrypted_data_1"
    },
    "base64_data_2" : {
      "content": "base64_encrypted_data_2"
    },
    ...
    "base64_data_N" : {
      "content": "base64_encrypted_data_N"
    },
  ]
}
```

Given crypto_service.rs already exists and provides sign/verify (and sign_map/verify_map) functions
When adding encrypt support
Then add encrypt and encrypt_map functions, using verify/verify_map and sign/sign_map as examples
And use base64 decode to extract the data key value
And use the public key to encrypt the data using public_key.encrypt() (instead of signing)
And then return the data_map with the 'content' CryptoContent field populated with the result
And use public_key.encrypt().to_bytes() to get the raw bytes (from encrypt function), then use base64 encode to safely place the encrypted data in the data_map 'content' variable (in encrypt_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/encrypt/{public_key} like /anttp-0/crypto/verify/{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
