2.0.8.9 - Winter '20 / API v47.0 Update

• Updated SOAP clients from API v47.0 WSDLs.
• Updated the internal API version to 47.0.
• Added 47.0 as an explicitly-selectable API version in the connection manager.
• Updated all LWC standard components for code completion and validation.
• Added support for the $MessageChannel Visualforce global variable and lightning:messageChannel Aura component.
• Added Winter '20 scratch org features for use in the scratch org creation dialog.
• Updated the Salesforce DX JSON schema files for sfdx-project.json and *-scratch-def.json code completion and validation.
• Updated the bundled SLDS CSS to 2.10.0.
• Updated metadata.xsd to v47.0 for code completion and validation in XML metadata files.
• Updated all bundled API documentation.
• Incremented the OST version number to prompt users to update their OSTs for Winter '20 changes.
• Other minor changes and improvements.