minor #32377 [Debug] Restoring back the state of the Debug component (1st step) (yceruto)
minor #32377 [Debug] Restoring back the state of the Debug component (1st step) (yceruto)

This PR was squashed before being merged into the 4.4 branch (closes #32377).

Discussion
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[Debug] Restoring back the state of the Debug component (1st step)

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | yes
| Tests pass?   | yes
| Fixed tickets | https://github.com/symfony/symfony/issues/32371
| License       | MIT

After a good discussion with @nicolas-grekas, we made the decision to split the current `ErrorCatcher` component into several:
 * `ErrorHandler` it would be the Debug component before these changes https://github.com/symfony/symfony/pull/31065, with everything related to ErrorHandler, Debug, DebugClassLoader classes and change its name.
 * `ErrorDumper` it would be the current ErrorCatcher but with FlattenException + the new error renderer system only.

This is the first step, then we can deprecate everything for the Debug component in favor of the ErrorHandler and ErrorDumper components, **BUT without moving any code !!**, that would give us more freedom to do it correctly in the new components.

NOTE: For this PR I've copy the `Debug` component directory from the revision prior to merged commit  https://github.com/symfony/symfony/pull/31065 in 4.4 branch.

Commits
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eda49e295e [Debug] Restoring back the state of the Debug component (1st step)

symfony/var-dumper,symfony/var-dumper