Create translation service por labels and emails content generation

[pferrariuy]

Required by issue #6

Generate a translation service capable to receiving a series of elementos and generate the corresponding translated elemento, depending in the Locale received as first parameter. Depending of the label, different parameters might be required to fill the final text, these parameters will be required for the correct translation.

List of elementos that need translation:

• [x] Settings (alert. and alert-category.)
• [x] Email alerts (email..subject and email.content.)
• [x] Overview alerts (alert.*)
• [x] Labels (general text to translate)

[pferrariuy]

Added new properties to application.properties file:

spring.mvc.locale = en
spring.messages.basename = lang/labels
spring.messages.encoding = UTF-8