Makefile displays a warning if $MANDIR is not in your manpaths or
$BINDIR is not in your $PATH. Expand paths $PREFIX (and by association $BINDIR and $MANDIR) before doing that validation or otherwise paths like '~/.local' and '/home/user/.local' will be erroneously reported different
Merge ui crate with root crate.
In preparation for uploading `meli` as a separate crate on crates.io.
Workspace crates will need to be published as well and having a separate
`ui` crate and binary perhaps doesn't make sense anymore.
- Add BINDIR, MANDIR env vars
- add check-dep target that checks for cargo/rustc version
- add ANSI formatting output with NO_COLOR support
- add help target
- move manpage installation to install-doc target
- move bin installation to install-bin target
- add dist target
- add warning if BINDIR is not inside $PATH
- add warning if MANDIR is not inside $MANPATH/manpath
