Add back validation on service struct

[NicolasMahe]

We need to add back the validation on the service, this time directly on the service.Service structure instead of the import.Service!

[NicolasMahe]

PR #1099 add the validation function but now a another PR is needed to actually call the validation!

[antho1404]

There is also validation missing:

• ports
• source
• "unique" validation for arrays
• make sure that the validation removed in the array is valid. What's the behavior when we send an array of null for example? We should require the values

[NicolasMahe]

Still missing some validation on Parameter keys: https://github.com/mesg-foundation/engine/pull/1110/files#r297480614

[NicolasMahe]

@krhubert Please check comment: https://github.com/mesg-foundation/engine/pull/1110/files#r297479535

[NicolasMahe]

@krhubert please check if can be close

[krhubert]

I've checked and the issue is still unresolved.

[krhubert]

 ›   Error: duplicated mapping key at line 20, column -25:
 ›              res:
 ›              ^

The validation for repeted object keys is imposible because json won't allow us to send the same data multiple time (the cli parse it as error), but I've added validation anyway :)