Create ftp.md

Corresponding to Using FTP from the docs website.
Not working urls removed.
Update ftp.md
Updating upgrade.md

Some of the links, such as FTP Client and http://docs.mybb.com/database_backup are actually not working, I tried to make an assumption based on the envisioned url structure for the new website.
Removed new line at the end of the document
Create chmod
Rename chmod to chmod.md
Updating chmod.md with actual content

Using FTP link is an assumption based on the envision url structure for the new website
Update ftp.md
Update ftp.md
Update chmod.md
Removing unnecessary newlines and moving to miscellaneous
Removing unnecessary newlines, moving to miscellaneous and adding bulleted list.
Removing unnecessary newlines
Merge #5