Remove unused types in our fork of server.go

[#62920758]

Signed-off-by: Abhijit Hiremagalur <abhi@pivotallabs.com>
Move server.go into its own package

To make it easier to see dependencies into the code we forked from net/http

[#62920758]

Signed-off-by: Eric Malm <emalm@pivotallabs.com>
Auto-merge remote-tracking branch 'upstream/master'