Fix imports after migration to 2024 edition.

Differences in Rust edition lead to compilation errors like the ones
below:

error[E0432]: unresolved import `sync`
  --> database/src/fs.rs:15:5
   |
15 | use sync::FlockMutexGuard;
   |     ^^^^ help: a similar path exists: `crate::sync`
   |
   = note: `use` statements changed in Rust 2018; read more at <https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-clarity.html>

error[E0432]: unresolved import `types`
  --> database/src/fs.rs:16:5
   |
16 | use types::{Email, Fingerprint, KeyID};
   |     ^^^^^ help: a similar path exists: `crate::types`
   |
   = note: `use` statements changed in Rust 2018; read more at <https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-clarity.html>

error[E0432]: unresolved imports `Database`, `Query`
  --> database/src/fs.rs:18:6
   |
18 | use {Database, Query};
   |      ^^^^^^^^  ^^^^^ no external crate `Query`
   |      |
   |      no external crate `Database`
   |
   = help: consider importing this trait instead:
           crate::Database
   = help: consider importing this enum instead:
           crate::Query

error[E0432]: unresolved import `wkd`
  --> database/src/fs.rs:20:5
   |
20 | use wkd;
   |     ^^^ no external crate `wkd`
   |
help: consider importing this module instead
   |
20 | use crate::wkd;
   |     +++++++

error[E0432]: unresolved import `openpgp_utils`
  --> database/src/fs.rs:25:5
   |
25 | use openpgp_utils::POLICY;
   |     ^^^^^^^^^^^^^ help: a similar path exists: `crate::openpgp_utils`
   |
   = note: `use` statements changed in Rust 2018; read more at <https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-clarity.html>

error[E0432]: unresolved import `types`
  --> database/src/sqlite.rs:11:5
   |
11 | use types::{Email, Fingerprint, KeyID};
   |     ^^^^^ help: a similar path exists: `crate::types`
   |
   = note: `use` statements changed in Rust 2018; read more at <https://doc.rust-lang.org/edition-guide/rust-2018/module-system/path-clarity.html>

error[E0432]: unresolved imports `Database`, `Query`
  --> database/src/sqlite.rs:13:6
   |
13 | use {Database, Query};
   |      ^^^^^^^^  ^^^^^ no external crate `Query`
   |      |
   |      no external crate `Database`
   |
   = help: consider importing this trait instead:
           crate::Database
   = help: consider importing this enum instead:
           crate::Query

error[E0432]: unresolved import `Email`
 --> database/src/openpgp_utils.rs:9:5
  |
9 | use Email;
  |     ^^^^^ no external crate `Email`
  |
help: consider importing this struct through its public re-export instead
  |
9 | use crate::Email;
  |     +++++++

Changes:
- Prefix imports with "crate::" as compiler suggest to fix the errors.

database/src/fs.rs

@@ -12,17 +12,17 @@ use std::time::SystemTime;
 use tempfile;
 use url::form_urlencoded;
 
-use sync::FlockMutexGuard;
-use types::{Email, Fingerprint, KeyID};
+use crate::sync::FlockMutexGuard;
+use crate::types::{Email, Fingerprint, KeyID};
 use Result;
-use {Database, Query};
+use crate::{Database, Query};
 
-use wkd;
+use crate::wkd;
 
 use tempfile::NamedTempFile;
 
 use openpgp::Cert;
-use openpgp_utils::POLICY;
+use crate::openpgp_utils::POLICY;
 
 use crate::DatabaseTransaction;
 

database/src/openpgp_utils.rs

@@ -6,7 +6,7 @@ use openpgp::{
     types::RevocationStatus, Cert,
 };
 
-use Email;
+use crate::Email;
 
 pub const POLICY: StandardPolicy = StandardPolicy::new();
 

database/src/sqlite.rs

@@ -8,9 +8,9 @@ use std::str::FromStr;
 use std::time::{SystemTime, UNIX_EPOCH};
 
 use openpgp::policy::StandardPolicy;
-use types::{Email, Fingerprint, KeyID};
+use crate::types::{Email, Fingerprint, KeyID};
 use Result;
-use {Database, Query};
+use crate::{Database, Query};
 
 use openpgp::Cert;
 

database/src/test.rs

@@ -26,14 +26,13 @@ use openpgp::{
     types::RevocationStatus,
     Cert, Packet,
 };
-use types::{Email, Fingerprint, KeyID};
-use Database;
-use Query;
+use crate::types::{Email, Fingerprint, KeyID};
+use crate::{Database, Query};
 
-use openpgp_utils::POLICY;
+use crate::openpgp_utils::POLICY;
 
-use EmailAddressStatus;
-use TpkStatus;
+use crate::EmailAddressStatus;
+use crate::TpkStatus;
 
 use crate::DatabaseTransaction;