The class is in charge of performing operations to an image
as if a user is performing those actions from the image editor
but from the BE. This class is a utility class to be used
from within the test context to mimic the user behavior of
performing edits into an image.

When an image is edited the `sources` properties is going to be backup with
the rest of the sizes properties, however that's not the case for the `full`
size which is a virtual type and the top level `sources` would be moved
into the backup metadata.

When the image is restored any edited image available in the sources array would
be removed before the restore takes place. The `sources` property for the `full-orig`
would be placed at the top level `sources` with the rest of the metadata.

This would be handled once #158 is merged so
the current approach can be adjusted accordingly.

When an image is edited using a target other than the
all and the thumbnail make sure the `success` method
returns the correct value.

Due to the only value that is not correctly stored is
the top level sources attributes this now is stored
in a separate meta value. Stored in `_wp_attachment_backup_sources`

Logic was added to handle scenarios where only the thumbnail
or all images except the thumbnail are modified.

Co-authored-by: Felix Arntz <felixarntz@users.noreply.github.com>

Co-authored-by: Felix Arntz <felixarntz@users.noreply.github.com>

Co-authored-by: Felix Arntz <felixarntz@users.noreply.github.com>

Co-authored-by: Felix Arntz <felixarntz@users.noreply.github.com>

Move the hooks for the update right into the place where they are
actually used.

Co-authored-by: Felix Arntz <felixarntz@users.noreply.github.com>

Co-authored-by: Felix Arntz <felixarntz@users.noreply.github.com>

The `backup_sizes` parameter was not used so it can be safely removed
from the code execution.

Reuse the hook as now is stored in a variable, so it can be reused in
both hooks.

Co-authored-by: Eugene Manuilov <manuilov@google.com>

Co-authored-by: Eugene Manuilov <manuilov@google.com>

Co-authored-by: Eugene Manuilov <manuilov@google.com>

Co-authored-by: Eugene Manuilov <manuilov@google.com>

Make sure the code performns in a more structured way