avoid chrono dependency, depend on proxmox 0.3.8

- remove chrono dependency

- depend on proxmox 0.3.8

- remove epoch_now, epoch_now_u64 and epoch_now_f64

- remove tm_editor (moved to proxmox crate)

- use new helpers from proxmox 0.3.8
  * epoch_i64 and epoch_f64
  * parse_rfc3339
  * epoch_to_rfc3339_utc
  * strftime_local

- BackupDir changes:
  * store epoch and rfc3339 string instead of DateTime
  * backup_time_to_string now return a Result
  * remove unnecessary TryFrom<(BackupGroup, i64)> for BackupDir

- DynamicIndexHeader: change ctime to i64

- FixedIndexHeader: change ctime to i64

src/api2/node/time.rs

@@ -1,4 +1,3 @@
-use chrono::prelude::*;
 use anyhow::{bail, format_err, Error};
 use serde_json::{json, Value};
 
@@ -57,10 +56,11 @@ fn read_etc_localtime() -> Result<String, Error> {
 )]
 /// Read server time and time zone settings.
 fn get_time(_param: Value) -> Result<Value, Error> {
-    let datetime = Local::now();
-    let offset = datetime.offset();
-    let time = datetime.timestamp();
-    let localtime = time + (offset.fix().local_minus_utc() as i64);
+    let time = proxmox::tools::time::epoch_i64();
+    let tm = proxmox::tools::time::localtime(time)?;
+    let offset = tm.tm_gmtoff;
+
+    let localtime = time + offset;
 
     Ok(json!({
         "timezone": read_etc_localtime()?,