feat: Add the ability to login users automatically

[cbaker6]

New Pull Request Checklist

• I am not disclosing a vulnerability.
• I am creating this PR in reference to an issue.

Issue Description

Currently there is now to automatically login a user.

Approach

Add the ability to configure the SDK to allow automatic login by setting usingAutomaticLogin to true or by calling try await User.enableAutomaticLogin() at anytime after SDK initialization.

The automatic login leverages ParseAnonynous to login, so anonymous login needs to be enabled on the Parse Server to use this feature.

TODOs before merging

• Add tests
• Add entry to changelog
• Add changes to documentation (guides, repository pages, in-code descriptions)

[codecov]

Codecov Report

Merging #98 (5ba4c59) into main (2180ca6) will increase coverage by 0.08%.
The diff coverage is 94.11%.

@@            Coverage Diff             @@
##             main      #98      +/-   ##
==========================================
+ Coverage   91.51%   91.60%   +0.08%     
==========================================
  Files         172      172              
  Lines       15347    15385      +38     
==========================================
+ Hits        14045    14093      +48     
+ Misses       1302     1292      -10     

Impacted Files	Coverage Δ
Sources/ParseSwift/Types/ParseVersion.swift	98.61% <ø> (ø)
...Authentication/Protocols/ParseAuthentication.swift	90.37% <85.00%> (+4.41%)	⬆️
...tication/Protocols/ParseAuthentication+async.swift	100.00% <100.00%> (+11.42%)	⬆️
Sources/ParseSwift/Objects/ParseUser.swift	93.71% <100.00%> (+0.11%)	⬆️
Sources/ParseSwift/Parse.swift	97.16% <100.00%> (+0.02%)	⬆️
Sources/ParseSwift/Types/ParseConfiguration.swift	97.95% <100.00%> (+0.08%)	⬆️

... and 1 file with indirect coverage changes