Refactor and improve CSV adapter

[yunzheng]

This change allows the CSV adapter to:

• properly read reserved field names (eg: _generated, _source, etc)
• use clean_fieldname that otherwise are invalid names in flow.record
• deduce format of csv file automatically by using csv.Sniffer

[codecov[bot]]

Codecov Report

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

Comparison is base (64263bc) 80.00% compared to head (131caad) 80.06%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #96 +/- ## ========================================== + Coverage 80.00% 80.06% +0.05% ========================================== Files 33 33 Lines 3101 3110 +9 ========================================== + Hits 2481 2490 +9 Misses 620 620 ``` | [Flag](https://app.codecov.io/gh/fox-it/flow.record/pull/96/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=fox-it) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/fox-it/flow.record/pull/96/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=fox-it) | `80.06% <100.00%> (+0.05%)` | :arrow_up: | 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=fox-it#carryforward-flags-in-the-pull-request-comment) to find out more.

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