Add the logger class
Add setter/getter methods for the log level
Return -EINVAL when adding a pool with empty args
Move the common defines to radosfsdefines.h
Make radosfsdefines.h auto-generated

This is so we can include the LOG_LEVEL_CONF_FILE (and possibly others
in the future) from the build system.
build: Generate the log level configuration file
build: Install the log level configuration file
build: Make the install prefix configurable
Destroy the pools' IO context when quitting
Don't add a pool if one with the same prefix exists
test: Test adding a pool with an existing prefix