Add ADBC Adapter

[TylerHillery]

No open issue by does relate to #383 (I didn't want to mark it as "resolves" as it's not technically a Snowflake specific adapter so I will leave that up to you to decide)

What are the key elements of this solution?
Adds adbc adapter as an extra

Why did you design your solution this way? Did you assess any alternatives? Are there tradeoffs?
Followed typical PR format for adding an adapter as an extra

Does this PR require a change to Harlequin's docs?

• No.
• Yes, and I have opened a PR at tconbeer/harlequin-web.
• Yes; I haven't opened a PR, but the gist of the change is: Need to add ADBC adapter docs

Did you add or update tests for this change?

• Yes.
• No, I believe tests aren't necessary.
• No, I need help with testing this change.

Please complete the following checklist:

• I have added an entry to CHANGELOG.md, under the [Unreleased] section heading. That entry references the issue closed by this PR.
• I acknowledge Harlequin's MIT license. I do not own my contribution.

[TylerHillery]

I am an idiot 🤦‍♂️ I added harlequin-adbc = { version = "^0.1", python = ">=3.9.0", optional = true } then ran poetry lock forgetting to add adbc = ["harlequin-adbc"] so I went back to add it forgetting to run poetry lock again afterwards