refactor: rolling file appender as one single solution

[tisonkun]

• This fixes Log file name style #143
• This fixes Rolling file appender overgrows x.log.0 on restart when max_file_size is set #153

The rotate strategy is:

from:
app.log
app.1.log
app.2.log

to:
app.log
app.1.log - old app.log
app.2.log - old app.1.log
- old app.2.log deleted

[Mota-Link]

LGTM

[nine9ths]

Sorry, a little late to the party, should it just be called FileAppender now that it handles the rolling and static file cases?

[tisonkun]

called FileAppender

Sounds reasonable. I may consider rename it as append::File, or if you have time, welcome to do the rename :D