Implement CLI history command

[pires]

• CHANGELOG.md updated
• Rebased/mergeable
• Tests pass
• Sign CLA (if not already signed)

Pay special attention to the a couple facts:

• exit command returns false, thus it's not stored in the history file.
  • https://github.com/influxdb/influxdb/blob/master/cmd/influx/main.go#L265
  • https://github.com/influxdb/influxdb/blob/master/cmd/influx/main.go#L243
• any invalid command, e.g. x is always treated as a query statement and thus is stored in the history file.
  • https://github.com/influxdb/influxdb/blob/master/cmd/influx/main.go#L297

Now, the output:

$ influx -host 192.168.99.100
Visit https://enterprise.influxdata.com to register for updates, InfluxDB server management, and monitoring.
Connected to http://192.168.99.100:8086 version 0.9.3
InfluxDB shell 0.9
> history
help
history
help
history
show databases
show tag values
help
history
x
history
x
history
>

Fixes #4628

[corylanou]

+1

[otoolep]

+1

[otoolep]

Looks good, thanks @pires - this change exposed 1 minor issue with history in general, for which I opened #4719.