Duplicate code blocks

Description

Added a new analyzer that can find duplicate code blocks using PMD's CPD tool. Closes #164 (closed)

Changes

None

Additions

• New CPD analyzer
• PMD dependency in checker
• New metric type

Test and Review

To be filled in by the reviewers

• All of the methods are commented to expectation

• The methods are tested to satisfaction

• There are no unnecessary files present in the MR

• The continuous integration has no problems with the MR

• The MR is filled in as requested (including labels, milestones, and reviewers)

• The documentation is up-to-date

• All nullable parameters are marked as such