Create initial project structure

The initial project structure includes the base scaffolding of the
application as well as the ability to fetch the repo list from the
remote endpoint.

src/cli.rs

@@ -0,0 +1,70 @@
+#![allow(unused_imports)]
+
+use clap::Args;
+use clap::Parser;
+use clap::Subcommand;
+use clap::ValueEnum;
+use std::ffi::OsString;
+use std::path::PathBuf;
+
+#[derive(Debug, Parser)]
+#[command(name = "dredge", version, author)]
+#[command(about =  "A Docker Registry CLI tool", long_about = None)]
+pub(crate) struct Cli {
+    #[command(subcommand)]
+    pub command: Commands,
+
+    #[arg(short = 'c', long = "config")]
+    pub config: Option<OsString>,
+
+    #[arg(
+        long = "log-level",
+        require_equals = true,
+        value_name = "LEVEL",
+        num_args = 0..=1,
+        default_value_t = LogLevel::Info,
+        default_missing_value="info",
+        value_enum
+    )]
+    pub log_level: LogLevel,
+}
+
+#[derive(ValueEnum, Copy, Clone, Debug, PartialEq, Eq)]
+pub enum LogLevel {
+    Trace,
+    Debug,
+    Info,
+    Warn,
+    Error,
+    Off,
+}
+
+impl From<LogLevel> for log::LevelFilter {
+    fn from(lvl: LogLevel) -> Self {
+        match lvl {
+            LogLevel::Trace => Self::Trace,
+            LogLevel::Debug => Self::Debug,
+            LogLevel::Info => Self::Info,
+            LogLevel::Warn => Self::Warn,
+            LogLevel::Error => Self::Error,
+            LogLevel::Off => Self::Off,
+        }
+    }
+}
+
+#[derive(Debug, Subcommand)]
+pub enum Commands {
+    Repo(RepoArgs),
+}
+
+#[derive(Debug, Args)]
+pub struct RepoArgs {
+
+    #[command(subcommand)]
+    pub command: RepoCommands,
+}
+
+#[derive(Debug, Subcommand)]
+pub enum RepoCommands {
+    List,
+}