Implemented methods concerning removability in a matching covered graph

[janmenjayap]

The objective of this issue is to implement the methods pertaining to removability in a matching covered graph.

More specifically, this PR aims to implement the following methods:

• is_removable_edge() | Check whether the edge is removable.
• is_removable_doubleton() | Check whether the pair of edges constitute a removable doubleton.
• is_removable_ear() | Check whether the ear is removable.
• is_removable_double_ear() | Check whether the pair of ears form a removable double ear.
• removable_edges() | Return a :class:~EdgesView of removable edges.
• removable_doubletons() | Return a list of removable doubletons.
• removable_ears() | Return a list of removable ears.
• removable_double_ears() | Return a list of removable double ears.

This PR shall address the methods related to removable edges, removable ears, removable doubletons and removable double ears of matching covered graphs.

Fixes #38216.
Note that this issue fixes a small part of the mentioned issue.

📝 Checklist

• The title is concise and informative.
• The description explains in detail what this PR is about.
• I have linked a relevant issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation and checked the documentation preview.

⌛ Dependencies

This PR depends on the PR #38742.

cc: @dcoudert .

[github-actions]

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