Add functionality to execute a user defined teardown after each test

[gianfra-t]

As part of #26, the tokens used are now persistent in the standalone chain (or any chain used to test the contracts).

This introduces a different behavior and one must be aware when running tests that the tokens minted will persist after each run.
For this reason, some tests were modified in #26 to add a burn function before the minting, to ensure that the token balance starts at 0. (see this for example).

Proposed Enhancement

It would be interesting to have an analogous to the setUp function called teardown for example, that gets executed after each test suite runs no matter if the execution is successful or not.

[gianfra-t]

@pendulum-chain/product The purpose of this ticket is to make a bit easier the writing and readability of tests. As of now it is completely possible to perform the same behavior just using the setUp function.

[prayagd]

Hey team! Please add your planning poker estimate with Zenhub @adelarja @b-yap @ebma @TorstenStueber

[prayagd]

Please add your planning poker estimate with Zenhub @gianfra-t

[prayagd]

@gianfra-t i assume this is nice to have right? If yes can i move this to icebox?

[gianfra-t]

Yes it is a nice to have for the developer, not at all something that will add some extra capabilities.

[TorstenStueber]

This should be quite doable and, as far as I understand, is more powerful than what forge provides.