[Validator] Fix constraint violation message parameterization
[Validator] Fixed value-to-string conversion in constraint violations
[Validator] Simplified IBAN validation algorithm
[Validator] Fixed and simplified IsbnValidator
[Validator] Simplified IssnValidator
[Validator] Simplified and explained the LuhnValidator
[Validator] Added "{{ value }}" parameters where they were missing
[Validator] Fixed date-to-string conversion tests to match ICU 51
[Validator] Fixed CS
[Validator] Renamed valueToString() to formatValue(); added missing formatValue() calls
[Validator] Removed information from the violation output if the value is an array, object or resource

This was decided in the discussion of #10687.
[Validator] Added more detailed inline documentation
bug #10687 [Validator] Fixed string conversion in constraint violations (eagleoneraptor, webmozart)

This PR was merged into the 2.3 branch.

Discussion
----------

[Validator] Fixed string conversion in constraint violations

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #10675
| License       | MIT
| Doc PR        | -

Commits
-------

32ae95b [Validator] Added more detailed inline documentation
08ea6d3 [Validator] Removed information from the violation output if the value is an array, object or resource
d6a783f [Validator] Renamed valueToString() to formatValue(); added missing formatValue() calls
71897d7 [Validator] Fixed CS
cea4155 [Validator] Fixed date-to-string conversion tests to match ICU 51
5aa7e6d [Validator] Added "{{ value }}" parameters where they were missing
f329552 [Validator] Simplified and explained the LuhnValidator
bff09f2 [Validator] Simplified IssnValidator
224e70f [Validator] Fixed and simplified IsbnValidator
fd58870 [Validator] Simplified IBAN validation algorithm
97243bc [Validator] Fixed value-to-string conversion in constraint violations
75e8815 [Validator] Fix constraint violation message parameterization