shell - manager - allow to install plugins in non interactive mode

Let people do `restx shell install <pluginid>` to easily script a restx install
shell - app - add compile and generate-start-script commands

- app compile can be used to compile all app classes
- app generate-start-script can be used to generate start.sh and start.bat

Also added --fg option to app run to run the app in foreground

These can be used to batch setup of a restx app like this:

`restx deps install + app compile + app generate-start-script && ./start.sh`

OR

`restx deps install + app compile + app run --mode-prod --fg`

--fg is especially useful to use that in a docker container
jetty - make JettyWebServer runnable, easing launching a jetty web server on a webapp base package

eg
`java -cp "target/dependency/*" restx.server.JettyWebServer path/to/webapp`