Added tuple modules

[varonroy]

Checklist

• Confirmed that run-checks all script has been executed.
• Made sure the book is up to date with changes in this PR.
  • This change is not significant enough to warrant an addition to the book.

Related Issues/PRs

Related to issue: #1046.

Changes

This PR provides an implementation for tuple modules which reduce the amount of code that needs to written in some cases. Tuple modules also allow another way to group modules besides structs.

#[derive(Module, Debug)]
pub struct MyModule<B: Backend> {
    linear: Linear<B>,
    block: (
        Linear<B>,
        ReLU,
        Linear<B>,
        ReLU,
    ),
}

Previously, creating a structure similar to the block field above would require creating a separate struct.

#[derive(Module, Debug)]
pub struct Block<B: Backend> {
    l1: Linear<B>,
    act1: ReLU,
    l2: Linear<B>,
    act2: ReLU,
}

Testing

ModuleComposed in burn-core/tests/derive-module.rs has been modified with an additional tuple field and all tests have passed.

[codecov]

Codecov Report

Attention: 22 lines in your changes are missing coverage. Please review.

Comparison is base (8686082) 84.45% compared to head (d7768b5) 84.44%.
Report is 1 commits behind head on main.

Files	Patch %	Lines
burn-core/src/module/param/primitive.rs	36.00%	16 Missing ⚠️
burn-core/src/record/primitive.rs	0.00%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1186      +/-   ##
==========================================
- Coverage   84.45%   84.44%   -0.02%     
==========================================
  Files         546      546              
  Lines       61507    61596      +89     
==========================================
+ Hits        51946    52014      +68     
- Misses       9561     9582      +21     

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[nathanielsimard]

Only a single minor comment, thanks a lot for the contribution!