feat(compileRest): allow to reuse the rest settings, to generate rest path from parameters

[thib3113]

This PR allow to call a endpoint to generate the rest url .

allow to do :

const svc = {
 name: "users",
 settings: {
  rest: '/users'
 },
 actions: {
  action: {
    rest: 'GET /:id'
  }
 }
}

await ctx.call('gateway.getRest', {action: 'my.action', params: {id:123}}); // => return /users/123

It can be usefull if you want to setup hypermedias, or just generate a link

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I'm not sure about the naming, so I reuse the naming from path-to-regexp "compile" .

Not sure about the error throw if missing parameters, but it seems that path-regexp throw an error if a parameter is missing (I also tried with parameter validate to false) .

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State of the PR :

• write tests
• write documentation

[icebob]

Good idea, please add relevant tests as well