models: Add Strength enum and Setting-Generator struct

We need to add these to match changes in Bottlerocket-core-kit
Refer commit:
bottlerocket-os/bottlerocket-core-kit@a72f6bd

PR: bottlerocket-os/bottlerocket-core-kit#294

sources/models/Cargo.toml

@@ -14,6 +14,7 @@ bottlerocket-release.workspace = true
 libc.workspace = true
 serde = { workspace = true, features = ["derive"] }
 serde_json.workspace = true
+serde_plain.workspace = true
 toml.workspace = true
 
 # settings plugins

sources/models/src/lib.rs

@@ -25,6 +25,7 @@ use bottlerocket_release::BottlerocketRelease;
 use bottlerocket_settings_models::model_derive::model;
 use bottlerocket_settings_plugin::BottlerocketSettings;
 use serde::{Deserialize, Serialize};
+use serde_plain::derive_fromstr_from_deserialize;
 use std::collections::HashMap;
 
 use bottlerocket_settings_models::modeled_types::SingleLineString;
@@ -87,3 +88,56 @@ struct Report {
     name: String,
     description: String,
 }
+
+/// Strength represents whether the settings can be overridden by a setting generator or not.
+#[derive(Deserialize, Serialize, Debug, Clone, Copy, PartialEq)]
+#[serde(rename_all = "kebab-case")]
+pub enum Strength {
+    Strong,
+    Weak,
+}
+
+impl std::fmt::Display for Strength {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Strength::Strong => write!(f, "strong"),
+            Strength::Weak => write!(f, "weak"),
+        }
+    }
+}
+
+derive_fromstr_from_deserialize!(Strength);
+
+/// Struct to hold the setting generator definition containing
+/// command, strength, skip-if-populated
+#[derive(Deserialize, Serialize, std::fmt::Debug, PartialEq)]
+
+pub struct SettingsGenerator {
+    pub command: String,
+    pub strength: Strength,
+    #[serde(rename = "skip-if-populated")]
+    pub skip_if_populated: bool,
+}
+
+impl SettingsGenerator {
+    pub fn is_weak(&self) -> bool {
+        self.strength == Strength::Weak
+    }
+
+    pub fn with_command(command: String) -> Self {
+        SettingsGenerator {
+            command,
+            ..SettingsGenerator::default()
+        }
+    }
+}
+
+impl Default for SettingsGenerator {
+    fn default() -> Self {
+        SettingsGenerator {
+            command: String::new(),
+            strength: Strength::Strong,
+            skip_if_populated: true,
+        }
+    }
+}