If `PREFIX` is `/usr` then `logdir`, `rundir` and `localstatedir`
should not contain the prefix.
**Global default configuration**: Based on the `--prefix` used during
installation/make global config should be installed in
`$PREFIX/etc/glusterfs/glusterd2.toml`. All the default values from
code should be moved to this file.
**Removed logic to pick config file from current directory**: Since
Glusterd2 will be run as daemon or background process, automatically
picking config file from current directory will add confusion to
users. For development, if global config file not exists then it loads
config file from the current directory.
**Config file as argument**: Glusterd2 applies global configurations
first and then applies this configuration to overwrite the values
if any.
Signed-off-by: Aravinda VK <avishwan@redhat.com>
