fix: return an error on clone creation failing, update the idle timeout parameter

Description

• Avoid panic after failed creation by checking the clone status

2020/02/29 22:25:15 http: panic serving 127.0.0.1:53526: runtime error: invalid memory address or nil pointer dereference
goroutine 8 [running]:
net/http.(*conn).serve.func1(0xc000275ae0)
        /usr/local/go/src/net/http/server.go:1767 +0x139
panic(0x8cbbe0, 0xd2f4c0)
        /usr/local/go/src/runtime/panic.go:679 +0x1b2
gitlab.com/postgres-ai/joe/pkg/bot.(*Bot).runSession(0xc0002e0280, 0xa20a40, 0xc00002a060, 0xc00010c1e0, 0xc000340880, 0x9, 0xa, 0x0)

• Change the name of idle timeout parameter in configs to maxIdleMinutes

Checklist

• the MR description has been reviewed
• this MR contains text changes and they have been reviewed OR there are no texts changes
• this MR contains GUI/CLI changes and they have been reviewed OR there are no GUI/CLI changes
• this MR contains API changes, specifications reflect those changes and they have been reviewed OR there are no API changes