refactor(sqlite): Resolve duplicate test target warning for macros.rs

[iamjpotts]

Does your PR solve an issue?

Resolves this cargo warning:

warning: ./Cargo.toml: file `./tests/sqlite/macros.rs` found to be present in multiple build targets:
  * `integration-test` target `sqlite-macros`
  * `integration-test` target `sqlite-unbundled-macros`

Merges the two target definitions in Cargo.toml and moves the sqlite vs sqlite-unbundled feature check to the top of the macros.rs module.

Is this a breaking change?

No; only affects test target configuration.

[abonander]

There's a pseudo-feature specifically for this:

Suggested change

	required-features = ["macros"] # Also requires either sqlite or sqlite-unbundled
	required-features = ["_sqlite", "macros"] # Also requires either sqlite or sqlite-unbundled

I think sometime in the future we could change it to sqlite-bundled and sqlite-unbundled (or maybe sqlite-bindgen), and then the sqlite feature just enables libsqlite3-sys without any linkage features.

The blocker on that is that the pre-generated bindings libsqlite3-sys uses by default are based on SQLite 3.14, but we unconditionally depend on sqlite3_prepare_v3() which wasn't added until 3.20: https://www.sqlite.org/changes.html#version_3_20_0

If they would be amenable to adding a min_sqlite_version_3_20 feature, or a prepare-v3 feature, I think we could make it work out-of-the-box.

[abonander]

Opened rusqlite/rusqlite#1731

[abonander]

Suggested change

#![cfg(any(feature = "sqlite", feature = "sqlite-unbundled"))]

[iamjpotts]

Made both adjustments to use _sqlite feature; warning is still fixed.