Added attribute whitelisting in the escaper framework to prevent arbitrary code execution

There was no proper whitelisting of attributes to prevent arbitrary code execution.

This vulnerability affects the following application versions:

• Magento 2.2.0
• Magento 2.2.0-rc2.0
• Magento 2.2.0-rc2.1
• Magento 2.2.0-rc2.2
• Magento 2.2.0-rc2.3
• Magento 2.2.0-rc3.0
• Magento 2.2.1
• Magento 2.2.2
• Magento 2.2.3
• Magento 2.2.4
• Magento 2.2.5
• Magento 2.2.6
• Magento 2.2.7
• Magento 2.2.8
• Magento 2.2.9
• Magento 2.2.10
• Magento 2.2.11
• Magento 2.3.0
• Magento 2.3.1
• Magento 2.3.2
• Magento 2.3.2-p1
• Magento 2.3.2-p2
• Magento 2.3.3
• Magento 2.3.3-p1
• Magento 2.3.4