Add parachain testing

[joelamouche]

tackles #132 and #146

[joelamouche]

@shawntabrizi So the framework setup allows a simple read.
But when trying to test an xcm, I get

     TypeError: Cannot read property 'registerAsset' of undefined
      at registerAssetToParachain (test/tests/test-xcm-para.ts:52:36)

which suggests that xcm are not in the cumulus build. Is that true?

[joelamouche]

Also, do we want tests in the CI? One xcm test takes about 5mn and the whole xcm seq is about 30mn

[joelamouche]

@shawntabrizi ready for review

[joelamouche]

@shawntabrizi updated

[joelamouche]

@shawntabrizi ready to merge

[shawntabrizi]

sorry for delays. new version has been published

[apopiak]

@joelamouche Could you add some description and usage info here and/or in the code?
4k lines is a lot to skim to figure out what this does.

[joelamouche]

@apopiak 3700 are from the lock file ^^
But yes sure I'd love to add more information. Do you mind creating an issue and assigning it to me pls? That way I don't forget