ERC721Consecutive with custom startingTokenId

[kfishnchips]

🧐 Motivation
Many of our contracts start with token id 1, ERC721Consecutive currently assumes the starting token id to be zero.

📝 Details
Add a constructor which allows setting the starting token id.

[frangio]

@kfishnchips What was the reason for closing this issue?

[kfishnchips]

I opened a PR instead, apologies.

[kfishnchips]

@frangio this is the PR #4097, should I keep this issue open?