Delete older backup files

[dimsav]

Two configuration options:

• max files mode
• time_machine mode: after 30 days, allow 1 per week. after 6 months, allow 1 per month

[markitosgv]

I trying to carry on this feature. I forked repo, at first im going to develop max files mode. First of all i make when you store files, put into folders, i mean, sql files in myproyect/sql/date_sql.sql and directory files in myproyect/files/dateproyect_upload.zip, it easier then delete old files.

[dimsav]

Nice! Feel free to open a pull request :)