add zora drops strategies

[neatonk]

See #256

[TimDaub]

Overall looks very good and mergable. Just one minor thing is that I spontaneously changed the strategy transformer interface and so now messages isn't a required property anymore, check it here: 5b087b5

[neatonk]

Overall looks very good and mergable. Just one minor thing is that I spontaneously changed the strategy transformer interface and so now messages isn't a required property anymore, check it here: 5b087b5

I've fixed the transformer interface. Might as well merge this when ready so it doesn't fall out of sync with the main branch. The missing zora-drops-get-tokenuri strategy can be added in another PR.

[TimDaub]

ok I ran all tests locally and this seems to work