clean_blank_lines: Add a new function to clean blank Lines

This functions removes all blan lines from a block of text e.g

input = ```
foo

bar

foobar
```

output=```
foo
bar
foobar
```

functions/clean_blank_lines.pp

@@ -0,0 +1,8 @@
+# @summary Remove blank lines from a string
+# @param content The content to remove blank lines from
+# @return The content with blank lines removed
+function extlib::clean_blank_lines (
+  String[1] $content,
+) >> String[1] {
+  return $content.split("\n").filter |$x| { !$x.empty }.join("\n")
+}

spec/functions/clean_blank_lines_spec.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+input = <<-TEXT
+  string_name: "string_value"
+
+  int_name: 42
+
+  true_name: yes
+TEXT
+output = <<-TEXT
+  string_name: "string_value"
+  int_name: 42
+  true_name: yes
+TEXT
+
+describe 'extlib::clean_blank_lines' do
+  it { is_expected.to run.with_params(input).and_return(output) }
+end