Make the values in the time picker configurable

[AlonaNadler]

Kibana version:5.6

Elasticsearch version:5.6

Original install method (e.g. download page, yum, from source, etc.):

Description of the problem including expected versus actual behavior:
Currently, every user can choose their query timeframe in the time picker, as result users sometimes select to run a query over the last year and the cluster is coming under too much pressure.

Describe the feature:
Would like a way to configure the values users can see and run queries in time picker, for example, users will only be able to select a time range of last 14 days at max.

[Bargs]

Dupe of #2758