Includes integration test for most column types. Fixes #8918

* $__timeFrom() -> Returns the dashboard 'from' suitable for use querying
  against a MySQL TIMESTAMP field.
* $__timeTo() -> Returns the dashboard 'to' suitable for use querying
  against a MySQL TIMESTAMP field.
* $__unixEpochFiler(column) -> If you store timestamps as UNIX epoch's,
  this builds: column > 'from' AND column < 'to'
* $__unixEpochFrom() -> Returns the dashboard 'from' suitable for use querying
  against a MySQL integer field (UNIX epochs)
* $__unixEpochTo() -> Returns the dashboard 'to' suitable for use querying
  against a MySQL integer field (UNIX epochs)

* graphite-ds: add graphite version to config editor

* graphite-ds: modify add-graphite-function to show only version-related functions

* graphite-ds: refactor, move func filtering to gfunc.js

* graphite-ds: add new functions for graphite 1.0.x

* graphite-ds: fix unit tests (add jsonData)

fixes #8989

Icon adopted from grafana_icon.svg

Reference document:
https://developer.apple.com/library/content/documentation/AppleApplicati
ons/Reference/SafariWebContent/pinnedTabs/pinnedTabs.html

Fixes #8187