Sanitize strings properly

Core sanitization functions:

• AIPromptSegmentBase::buildPreview() - returns markup render element with html converted to html entities with new lines (br) preserved
• AIPromptCommons::prepareStatusMessage() - returns markup render element with html converted to html entities with new lines (br) preserved
• $aiprompt->buildPreview() - many Markup render elements for display to the user (for example, output prompt as views field)
• AIPromptSegmentBase::render() - returns raw not sanitized string for sending to AI in its original form
• AIPromptCommonEngineeringForm::displayOutputSubmit() - helper function to display prompt output for the user. Raw output is displayed either with ksm() function if devel module is enabled, or with $this->messenger()->addMessage($this->prepareStatusMessage($output))

Saving data to the database:

• Data is saved as either "data" json text basefield for content entity, or individual segment custom configuration values as "ignore" type for configuration entity.