[BUG] Make software kill and startup logs more graceful

[andrewnguyen22]

Describe the bug

The kill logs are quite jarring and don't actually mean anything bad

Jul 28 21:45:06.038 ERROR: Accept error: accept tcp [::]:9001: use of closed network connection
Jul 28 21:45:06.038 ERROR: Accept error: accept tcp [::]:9001: use of closed network connection
Jul 28 21:45:06.038 ERROR: Accept error: accept tcp [::]:9001: use of closed network connection
Jul 28 21:45:06.038 ERROR: Accept error: accept tcp [::]:9001: use of closed network connection
Jul 28 21:45:06.038 ERROR: Accept error: accept tcp [::]:9001: use of closed network connection
Jul 28 21:45:06.038 ERROR: Accept error: accept tcp [::]:9001: use of closed network connection

Jul 28 21:45:06.538 INFO: Exit command interrupt received
panic:
    Module:  store
    Code:    4
    Message: store.get() failed with err: DB::Get key: "c/\x7f\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\x00" err: DB Closed

goroutine 45 [running]:
github.com/canopy-network/canopy/store.NewSMT({0x19d2fc0, 0x20, 0x0?}, 0xa0, {0x1380600, 0xc00afcf4f0})
    /go/src/github.com/canopy-network/canopy/store/smt.go:159 +0x313
github.com/canopy-network/canopy/store.NewDefaultSMT(...)
    /go/src/github.com/canopy-network/canopy/store/smt.go:140
github.com/canopy-network/canopy/store.(*Store).NewReadOnly(0xc0068d4008, 0x63817)
    /go/src/github.com/canopy-network/canopy/store/store.go:148 +0x17b
github.com/canopy-network/canopy/fsm.(*StateMachine).TimeMachine(0xc01e4c4f08, 0x10?)
    /go/src/github.com/canopy-network/canopy/fsm/state.go:328 +0x82
github.com/canopy-network/canopy/cmd/rpc.(*Server).readOnlyState(0xe22960?, 0xc028352050?, 0xc01d877fa0)
    /go/src/github.com/canopy-network/canopy/cmd/rpc/server.go:254 +0x38
github.com/canopy-network/canopy/cmd/rpc.(*Server).updatePollResults.func1(...)
    /go/src/github.com/canopy-network/canopy/cmd/rpc/server.go:140
github.com/canopy-network/canopy/cmd/rpc.(*Server).updatePollResults(0xc023fd8008)
    /go/src/github.com/canopy-network/canopy/cmd/rpc/server.go:161 +0xb1
created by github.com/canopy-network/canopy/cmd/rpc.(*Server).Start in goroutine 1
    /go/src/github.com/canopy-network/canopy/cmd/rpc/server.go:81 +0x178

Expected Behavior

• Make kill 'panics' impossible
• Make accept errors silent in this context

Environment

• OS: Linux
• Software Version: Beta-0.1.8

Required Tags

• Priority: Backlog
• Module: Multi-Module

[andrewnguyen22]

Accept errors tacked with ef25f50