This commit upgrades the Netty dependencies from version 4.1.4 to version 4.1.5. This upgrade brings several bug fixes including the removal of a obnoxious and scary-looking log message when unsafe is explicitly disabled. Relates #20222
Removes our internal snapshot repo we used until 4.1.4 was released.
This commit adds transport-netty4, a transport and HTTP implementation based on Netty 4. Relates #19526