Refactored oxen log's CLI module to remove the 'arg!' macro
Refactored oxen log into two modules, a CLI module and a Lib module. The lib module is currently contains one function, "log commits", as that is the functionality it actually implements. This does make the naming a little inconsistent with the other lib modules, which typically have a function that is just the command name:
Ex: "pub use download::download", which has a 'download' function, vs. "pub use log::log_commits", which has no 'log' function
Refactored oxen remote log into its own module, following the formatting of remote df and remote commit
Three Changes: