Support template

[winebarrel]

Add the support of the following templates:

template "template 1" do
  read_only false
  board_bgtype "board_graph"
  original_title "my board"
  height context.height
  width "100%"
  template_variables []
  widgets []
  shared false
  title_edited true
end

template "template 2" do
  title_size 16
  title_align "left"
  title_text ""
  title true
end

screenboard "board1" do
  include_template "template 1", height: 80
end

screenboard "board2" do
  read_only false
  board_bgtype "board_graph"
  height 80
  width "100%"
  templated false
  widgets do |*|
    include_template "template 2"
    height 13
    tile_def do
      viz "timeseries"
      requests do |*|
        q "aws.dynamodb.provisioned_read_capacity_units{*}"
      end
      events []
    end
    width 47
    timeframe "1h"
    y 13
    x 10
    legend_size "0"
    type "timeseries"
    legend false
  end
end

Please marge if no problem 🙇

[marcy-terui]

Very useful ✨ Thanks a lot!!

[marcy-terui]

This is released in 0.3.0