Add support for AES

[heaths]

• [ ] Add EncryptAES, DecryptAES, etc. methods using a separate AESEncryptionAlgorithm so we can have different parameters in lieu of the EncryptParameters type and overloads in some other languages.
• [ ] Add optional Managed HSM resource and keys to resources.bicep.

[heaths]

Some notes from talking with @schaabs:

• AES CBC isn't really considered secure. Even AES CBC PAD using PKCS7 padding (which Go doesn't seem to support since messages must be a multiple of the block size) doesn't seem much better. Maybe it's not worth implementing client-side support and just remote everything.
• We will take the IV and plaintext/ciphertext and validate size as needed, but leave formatting e.g., prepending the IV to the output, to the caller. An example should show this.
• AES GCM may not be ideal for streaming ciphers because you really want to know if the full length will be a multiple of the block size; however, this is where some implementations like in .NET have methods like TransformBlock and TransformFinalBlock.
• We need a deterministic but unique nonce with each block. Starting at 0 and monotonically increasing or providing a large file offset are common approaches. Taking this and the previous point into consideration, to keep the Client stateless we could instead return an encryptor or decryptor that could either monotonically increase the nonce or just have a method on the Client (like we do in .NET et. al.) that requires the developer to get all this right...along with a suitable example for doing so.

[heaths]

Fixed by #49