* ISSUE-816: Spanish translation for menu entry Fluent->overview.
Also creating two files that are being referenced from overview file
* Related to ISSUE-816: Delete recently created 2 files because they are not translated and it is not necessary to have them because the system takes english in that case
* Related to ISSUE-816: Change .es.md extension in the links to only .md because it is managed automatically
* Code review done from jacortaf10
* Code review done from jacortaf10 part 2