DOMAINNAMESHOP: Adopt diff2 in compatibility mode

[tlimoncelli]

Hi @SimenBai:

In reference to replacing pkg/diff with the new pkg/diff2 (#1854)

I've introduced a compatibility mode to pkg/diff2 to make it easier for providers to adopt the new system. If you do a diff with "hide whitespace", you'll see the changes are minimal.

I've taken the liberty of providing this PR as a starting point.

Please run the integration tests and let me know the result. (If you're getting this, I probably don't have access to an account on this provider)

Please run:

    go test -v -verbose -provider DOMAINNAMESHOP

and

    go test -v -verbose -provider DOMAINNAMESHOP -diff2

They should both complete with no failures. Please fix any failures or loop me in for help.

If you are interested in porting to the new pkg/diff2/By*() functions, I'd be glad to accept a PR. However using the compatibility mode is sufficient if all tests pass.

Thanks and happy new years!!!

Tom
@tlimoncelli

[SimenBai]

I ran the tests and both of the runs passed. So there shouldn't be any issues with merging them.

[tlimoncelli]

Nice!

Thanks!