* Added a Julia client and server

This PR adds two new generators for the [Julia language](https://julialang.org/)
- `julia-client` to generate a client from specifications
- `julia-server` to generate a server with stubs that can be used to host a server conforming to the specifications

The generated code uses the Julia [OpenAPI.jl](https://github.com/JuliaComputing/OpenAPI.jl) package that includes support functions for both client and server.

* fix javadoc generation

* add changes after ensure-up-to-date run