Add new Quantikz rendering modules and enhance existing functions for visualization (#7354)

Feature(vis): Enhance circuit_to_latex_render and GIF creation

This PR introduces `cirq.contrib.quantikz` with the `render_circuit`
function
to produce circuit diagrams in LaTeX using the quantikz package.

The functionality is showcased and described here: in this Jupyter
notebook

https://drive.google.com/file/d/1KXQjBmQ9rNUjZHJ6QuGolthLN19_K9yK/view?usp=drivesdk
(colab:
https://colab.sandbox.google.com/drive/1KXQjBmQ9rNUjZHJ6QuGolthLN19_K9yK)

**Notes on `render_circuit`:**
* Performs upfront checks for `pdflatex` and `pdftoppm` executables.
Issues informative warnings and disables relevant functionality if they
are not found, preventing unexpected failures.
* If `pdflatex` fails and an `output_tex_path` is specified, the
problematic `.tex` file is copied to the specified path for easier user
inspection.

Example outputs: 

![image](https://github.com/user-attachments/assets/d941ab0d-30dc-4a01-aa85-aa4a4b1ef377)


![image](https://github.com/user-attachments/assets/79450bc3-25e6-46a8-9cf7-556b53a0722f)


![image](https://github.com/user-attachments/assets/d4b9013a-613b-4a6c-b2c2-50a04374ebe9)


![image](https://github.com/user-attachments/assets/e9d67a29-a6d5-4efb-abfd-cdfdce5a1422)


![image](https://github.com/user-attachments/assets/e0a36722-d066-473d-987c-b59850a88792)

---------

Co-authored-by: Doug Strain <dstrain@google.com>
Co-authored-by: Michael Hucka <mhucka@caltech.edu>
Co-authored-by: Pavol Juhas <juhas@google.com>

Author: 4 people

cirq-core/cirq/contrib/quantikz/__init__.py

@@ -0,0 +1,21 @@
+# Copyright 2025 The Cirq Developers
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Converts Cirq circuits to LaTeX diagrams using the Quantikz package."""
+
+from cirq.contrib.quantikz.circuit_to_latex_quantikz import (
+    CircuitToQuantikz as CircuitToQuantikz,
+    GATE_STYLES_COLORFUL as GATE_STYLES_COLORFUL,
+)
+from cirq.contrib.quantikz.circuit_to_latex_render import render_circuit as render_circuit