Add TypeScript and static types support to `service`

[Coinslist]

Summary

1. Add TypeScript support with adjustable compiler options inside service/tsconfig.json file
2. Add appropriate types for service/

[Coinslist]

Hi @wu-emma Please have a look at this (#16)

Thanks

[naftalimurgor]

Hey @Coinslist

• add npm script to transpile the TypeScript to JavaScript
• Update Dockerfile for /service
• Add coverage/ensure all tests pass Afterwards we shall review @wu-emma what are your views?

[wu-emma]

Ok, guys, please resolve merge conflicts, and then ping @van-orton if he would be able to test 'Typescripted'-bridge. Thanks for moving this forward!

[naftalimurgor]

@Coinslist @wu-emma Awsome. We are on it!