[d8] Add d8 backup loki option

[d2285]

This pr add d8 backup loki option to dump all logs from Loki api endpoint or in giver range timestamp.
e.g.

d8 backup loki --help
Dump Loki logs.

 This command dump all logs from Loki api or in given range timestamps in DKP.

 © Flant JSC 2025

Usage:
  d8 backup loki [flags]

Flags:
      --end string     Set end timestamp range to dump logs from Loki. (Default get max end timestamp from Loki, ex. "2025-01-14 15:04:05".)
  -h, --help           help for loki
      --limit string   Limit max string to output per queue from Loki. (Default 100000 max limit strings per queue.)
      --start string   Set start timestamp range to dump logs from Loki. (Default get max start timestamp from Loki, ex. "2025-01-12 15:04:05".)

Global Flags:
  -k, --kubeconfig string   KubeConfig of the cluster. (default is $KUBECONFIG when it is set, $HOME/.kube/config otherwise) (default "/root/.kube/config")

[d2285]

ex. output logs from Loki Api

Timestamp: [2025-02-20 13:30:26.371161215 +0000 UTC], Log: ts=2025-02-20T13:30:26.332Z caller=netdev_common.go:81 level=info collector=netdev msg="Parsed flag --collector.netdev.device-exclude" flag=^(veth.*|lxc.*|[a-f0-9]{15})$

Timestamp: [2025-02-20 13:30:26.371145721 +0000 UTC], Log: ts=2025-02-20T13:30:26.331Z caller=node_exporter.go:194 level=info msg="Build context" build_context="(go=go1.22.6, platform=linux/amd64, user=, date=, tags=unknown)"

Timestamp: [2025-02-20 13:30:26.371130298 +0000 UTC], Log: ts=2025-02-20T13:30:26.331Z caller=node_exporter.go:193 level=info msg="Starting node_exporter" version="(version=, branch=, revision=unknown)"