Implement infinite sums and products using lazy Laurent and Taylor series

[tscrim]

We should support these when each term/factor is strictly increasing in valuation. This can even be relaxed to weakly increasing, but then we allow the possibility it will run for forever.

CC: @mantepse

Component: algebra

Keywords: lazy power series, LazyPowerSeries

Issue created by migration from https://trac.sagemath.org/ticket/34404

[tscrim]

Description changed:

--- 
+++ 
@@ -1 +1 @@
-We should support these when each term/factor is strictly increasing in degree. This can even be relaxed to weakly increasing, but then we allow the possibility it will run for forever.
+We should support these when each term/factor is strictly increasing in valuation. This can even be relaxed to weakly increasing, but then we allow the possibility it will run for forever.

[mantepse]

Changed keywords from lazy power series to lazy power series, LazyPowerSeries

[mantepse]

Closing manually, because the PR has been merged.