feat(RingTheory/LocalRing/ResidueField/Fiber): the localization of Ideal.Fiber is a quotient

[tb65536]

This PR proves that the localization of Ideal.Fiber is a quotient. This will be applied in #39189 to prove the ramification-inertia formula for finite flat extensions.

---

[github-actions]

PR summary 767a1cedf4

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff

+ Ideal.Fiber.localizationAlgEquivQuotient

You can run this locally as follows

## from your `mathlib4` directory:
git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci

## summary with just the declaration names:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh <optional_commit>

## more verbose report:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh long <optional_commit>

The doc-module for scripts/pr_summary/declarations_diff.sh in the mathlib-ci repository contains some details about this script.

---

No changes to strong technical debt.

No changes to weak technical debt.