fix: make project compile without errors for both unit and e2e

[Hotell]

This fixes tsc errors so whole project with all code is compiled without errors, this is the demanded behaviour, it has one major caveat though -> testcafe's handling of TSC

because testcafe is not consuming user's provided tsconfig.json it will fail ofc, because there is no "skipLibCheck": true in testcafe's code.

Otherwise this is the "only right" solution how to compile whole project if Mocha/Testcafe is used ( which is needed , why ? -->

• you may need to reuse some functions/types from source code src/ ( this makes also TS very important, everything has 100% type safe contract implementation <--> tests, yummy )

Why this (works) ?:

• typescript type system is structural, and because both testcafe and mocha have same/similar type structure of test function, typescript consumes this with little issues which are resolved via skipLibCheck

Overall summary:

• this is rather a hack from Typescript perspective, because now when you write Testcafe tests it uses mocha type definition which may fail one day if whoever from those two ( TC, Mocha ) changes it's apis
• I'm not aware of any solution from typescript how to deal with this when handling global types cc @DanielRosenwasser @mhegazy
• Typings nightmare with @types/xxx microsoft/TypeScript#11437 (comment)

The correct way?:

• having base tsconfig for source and unit test compilation
• extending base tsconfig which excludes unit tests and includes e2e tests
  --> this is still not doable, because as I've mentioned, testcafe is unable to consume users tsconfig :(