feat(Analysis/Complex): periodic holo funcs factor through exponential

[loefflerd]

We show that a holomorphic function which is periodic with a real period h is given by f z = F (exp (2 * pi * I * z / h)) for some holomorphic F, and moreover, if f is bounded as Im z -> infty then F extends holomorphically to q = 0.

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These results will be used in a subsequent PR to define q-expansions for modular forms.