Add public getters for Node properties

[lorenzocerrone]

Feature requested in #12

Changes:

• implement three getter methods for the zarrs::Node struct

  /// Returns a reference to the path of the node.
  #[must_use] 
  pub fn path(&self) -> &NodePath {
      &self.path
  }
  
  /// Returns a reference to the metadata of the node.
  #[must_use]
  pub fn metadata(&self) -> &NodeMetadata {
      &self.metadata
  }
  
  /// Returns a reference to the metadata of the node.
  #[must_use]
  pub fn children(&self) -> &Vec<Node> {
      &self.children
  }

• Derived clone traits for zarrs::Node and zarrs::node::NodeMetadata

[codecov[bot]]

Codecov Report

Attention: 9 lines in your changes are missing coverage. Please review.

Comparison is base (ef43dbb) 81.63% compared to head (61e41ab) 81.59%.

Files	Patch %	Lines
src/node.rs	0.00%	9 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #13 +/- ## ========================================== - Coverage 81.63% 81.59% -0.04% ========================================== Files 127 127 Lines 18606 18615 +9 ========================================== Hits 15189 15189 - Misses 3417 3426 +9 ```

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[LDeakin]

Thanks @lorenzocerrone and best of luck with your project!

[lorenzocerrone]

Awesome, thanks a lot!