Created sum_of_harmonic_series.py (#7504)

* Created sum_of_harmonic_series.py

Here in this code the formula for Harmonic sum is not used, Sum of the series is calculated by creating a list of the elements in the given Harmonic series and adding all the elements of that list !

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* Update maths/sum_of_harmonic_series.py

Co-authored-by: Chris O <46587501+ChrisO345@users.noreply.github.com>

* Update maths/sum_of_harmonic_series.py

Co-authored-by: Chris O <46587501+ChrisO345@users.noreply.github.com>

* Update maths/sum_of_harmonic_series.py

Co-authored-by: Chris O <46587501+ChrisO345@users.noreply.github.com>

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* Update maths/sum_of_harmonic_series.py

Co-authored-by: Christian Clauss <cclauss@me.com>

* Update maths/sum_of_harmonic_series.py

Co-authored-by: Christian Clauss <cclauss@me.com>

* Update maths/sum_of_harmonic_series.py

Co-authored-by: Christian Clauss <cclauss@me.com>

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* Update sum_of_harmonic_series.py

* Add doctests

* Update sum_of_harmonic_series.py

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Chris O <46587501+ChrisO345@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>