Avoid raising plain exception

[EpicWink]

Raise a new CattrsError instead of built-in Exception, and make all other exceptions inherit from this.

This makes it more reliable to catch validation issues due to invalid literal or date-time values when structuring (instead of having to parse the exception message when catching Exception).

[codspeed-hq]

Merging this PR will not alter performance

✅ 54 untouched benchmarks

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_{Comparing EpicWink:literal-exception (7c8f9b5) with main (573915b)}

[Tinche]

I'm good with this; I was somewhat lazy in the past about it. Backwards compatibility should be fine, right?

[EpicWink]

Backwards compatibility should be fine, right?

@Tinche yes. Only possible breakages would be from some inane strict equality checks on Exception