feat: add support for sqliterc

[tconbeer]

Closes #325

What are the key elements of this solution? This essentially copies the implementation from the DuckDB adapter.

Why did you design your solution this way? Did you assess any alternatives? Are there tradeoffs? DuckDB's CLI was designed to copy SQLite's, so they share almost everything in common. It's simple enough and slightly different for the two dbs, so not worth factoring out into a shared module.

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

• [ ] No.
• [ ] Yes, and I have opened a PR at tconbeer/harlequin-web.
• [x] Yes; I haven't opened a PR, but the gist of the change is: sqlite adapter now supports init files.

Did you add or update tests for this change?

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

Please complete the following checklist:

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