Adding size limits for create secret json fields

Setting maxLength for name, algorithm, mode, expiration,
payload_content_type, and payload_content_encoding fields.

Payload size is already validated through other means.

Change-Id: Id48c5ca9e7af6e8a49591787a58427255eee10b7
Closes-Bug: #1335327
Merge "Adding size limits for create secret json fields"