Add FAQ/troubleshooting: metrics discrepancies + loki timeout

[openshift-ci[bot]]

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 66.55%. Comparing base (c1b4ee0) to head (50b48bd).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #663 +/- ## ======================================= Coverage 66.55% 66.55% ======================================= Files 70 70 Lines 8108 8108 ======================================= Hits 5396 5396 Misses 2316 2316 Partials 396 396 ``` | [Flag](https://app.codecov.io/gh/netobserv/network-observability-operator/pull/663/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=netobserv) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/netobserv/network-observability-operator/pull/663/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=netobserv) | `66.55% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=netobserv#carryforward-flags-in-the-pull-request-comment) to find out more.

[jotak]

(I'll go ahead and merge, this is only upstream docs)