Customize emails for cost usage reports

Abiquo will customize emails using template and properties files with the following priority:

Localized files for US English, such as costUsageReportTemplate_en_US.mustache and costUsageReport_en_US.properties
There is a known issue in Abiquo 6.2.0 where the server cannot find the properties file, so you cannot customize the subject of the mail
Files with no language code extension, such as costUsageReportTemplate.mustache and costUsageReport.properties
System defaults, with content as shown in the examples below

Log in to the Abiquo API Server as an administrator
In the config folder, if there is no mail folder, create a mail folder and set the owner as the tomcat user
```
/opt/abiquo/config/mail
```

In the mail folder, create the following files

Email file for notification of report ready for download

costUsageReportTemplate_en_US.mustache

<p>Hi {{username}},</p>
<p>Your cost usage report {{reportname}} has been generated. You can now download it from your Abiquo portal</p>
<p>To make any changes, please go to the Cost usage reports tab in the Abiquo platform and edit your scheduled reports.</p>
<p>Thank you,</p>
<p>The Abiquo Team</p>

Properties file for notification of report ready for download
There is a known issue in Abiquo 6.2.0 where the server cannot find the properties file, so you cannot customize the subject of the mail
costUsageReport_en_US.properties
```
subject=Abiquo cost usage report ready to download
```
If you change the subject property, you must restart the Tomcat server to apply your changes

Email file for notification of cancelled report
costUsageReportScheduleNotAvailableTemplate_en_US.mustache

<p>Hi {{username}},</p>
<p>A cost usage report with name {{reportname}} has been deleted and your schedule with id {{scheduleid}} is not available anymore.</p>
<p>You can access your scheduled reports through the "scheduled reports" section section within the Abiquo platform's Cost Usage Report view</p>
<p>Thank you,</p>
<p>The Abiquo Team</p>

Properties file for notification of cancelled report
costUsageReportScheduleNotAvailable_en_US.properties
```
subject=Abiquo cost usage report schedule not available anymore
```
If you change the subject property, you must restart the Tomcat server to apply your changes

Optionally add custom variables and content
1. In the email body, to add a custom variable, use double curly braces (also called double mustaches). For example
```
<p>Please call your system Administrator on <strong>{{helpline}}</strong></p>
```
2. Then in your properties file, set a value for your custom variable
```
helpline=555 12345
```
  To return unescaped HTML as part of a template property, use the triple mustache, which is {{{ and }}}.
  The Mustache templating software that adds the property values will escape HTML variables in double mustaches by default.
Change the owner of the files to the tomcat user