chore(crates): introduce new config crate for sprout configuration

crates/config/src/extractors.rs

@@ -0,0 +1,18 @@
+use crate::extractors::filesystem_device_match::FilesystemDeviceMatchExtractor;
+use serde::{Deserialize, Serialize};
+
+/// Configuration for the filesystem-device-match extractor.
+pub mod filesystem_device_match;
+
+/// Declares an extractor configuration.
+/// Extractors allow calculating values at runtime
+/// using built-in sprout modules.
+#[derive(Serialize, Deserialize, Debug, Default, Clone)]
+pub struct ExtractorDeclaration {
+    /// The filesystem device match extractor.
+    /// This extractor finds a filesystem using some search criteria and returns
+    /// the device root path that can concatenated with subpaths to access files
+    /// on a particular filesystem.
+    #[serde(default, rename = "filesystem-device-match")]
+    pub filesystem_device_match: Option<FilesystemDeviceMatchExtractor>,
+}