Add option to Export-Csv / ConvertTo-Csv for user-configurable formats

Summary of the new feature / enhancement

(follow-up to https://github.com/PowerShell/PowerShell/issues/19536)

In the current implementation of Export-Csv / ConvertTo-Csv, data is simply formatted using .ToString(), which uses the current culture's formats.

This is not always desirable -- for instance, milliseconds are lost in DateTime properties --, and changing the culture's format locally in code requires a non-obvious technique involving cloning the culture.

This would be tackled by adding a -Format option to Export-Csv / ConvertTo-Csv that would support specifying alternate formats on a per-property or per-type basis:

# (derived from @mklement0's proposals in https://github.com/PowerShell/PowerShell/issues/19536)
[pscustomobject] @{
  Name = 'foo'
  Ratio = 1 / 9
  Type = 'known'
  StartDate = Get-Date
  EndDate = (Get-Date).AddDays(1)
  Precise = 1 / 7
} | ConvertTo-Csv -Format @{ [datetime] = 'yyyy-MM-dd HH:mm:ss.fff'; [double] = 'F2'; Precise = 'F10' }

This would output:

"Name","Ratio","Type","StartDate","EndDate","Precise"
"foo","0.11","known","2023-04-27 17:23:28.540","2023-04-28 17:23:28.540","0.1428571429"

Proposed technical implementation details (optional)

No response

Start by reviewing the Export-Csv and ConvertTo-Csv cmdlets and the related discussion in issue 19536. Use the examples in this issue to clarify the proposed per-property and per-type -Format behavior, including DateTime precision and numeric formats. Done means the option's design and expected output are defined and covered for both cmdlets.