Added clippy to CI and fixed all clippy warnings (#613)

* Fixed all clippy warnings.

* Added `clippy` to CI.

* Reverted an unwanted change + Applied `cargo fmt`.

* Fixed the idiom version.

* Revert "Fixed the idiom version."

This reverts commit 6f78be0d42.

* Fixed clippy issues on CI.

* Revert "Fixed clippy issues on CI."

This reverts commit a9fa6ba189.

* Revert "Reverted an unwanted change + Applied `cargo fmt`."

This reverts commit 6bd37b6479.

* Revert "Fixed all clippy warnings."

This reverts commit d1f3b847e3.

* Removed Clippy

* Removed Lint

* `admin.rs` clippy fixes.

* Applied more clippy changes.

* Even more clippy changes.

* `client.rs` clippy fixes.

* `server.rs` clippy fixes.

* Revert "Removed Lint"

This reverts commit cb5042b144.

* Revert "Removed Clippy"

This reverts commit 6dec8bffb1.

* Applied lint.

* Revert "Revert "Fixed clippy issues on CI.""

This reverts commit 49164a733c.

src/plugins/intercept.rs

@@ -92,7 +92,7 @@ impl<'a> Plugin for Intercept<'a> {
                             .map(|s| {
                                 let s = s.as_str().to_string();
 
-                                if s == "" {
+                                if s.is_empty() {
                                     None
                                 } else {
                                     Some(s)

src/plugins/mod.rs

@@ -33,6 +33,7 @@ pub enum PluginOutput {
 #[async_trait]
 pub trait Plugin {
     // Run before the query is sent to the server.
+    #[allow(clippy::ptr_arg)]
     async fn run(
         &mut self,
         query_router: &QueryRouter,

src/plugins/prewarmer.rs

@@ -20,7 +20,7 @@ impl<'a> Prewarmer<'a> {
                 self.server.address(),
                 query
             );
-            self.server.query(&query).await?;
+            self.server.query(query).await?;
         }
 
         Ok(())

src/plugins/table_access.rs

@@ -34,7 +34,7 @@ impl<'a> Plugin for TableAccess<'a> {
 
         visit_relations(ast, |relation| {
             let relation = relation.to_string();
-            let parts = relation.split(".").collect::<Vec<&str>>();
+            let parts = relation.split('.').collect::<Vec<&str>>();
             let table_name = parts.last().unwrap();
 
             if self.tables.contains(&table_name.to_string()) {