Redesign documentation

[mariaschuld]

Turn the cirq documentation into Xanadu style. It is recommended to locally build the documentation for code review.

We do currently not have a lot of content, but this can be the basis of growing the plugin.

[codecov]

Codecov Report

Merging #25 into master will increase coverage by 0.62%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #25      +/-   ##
==========================================
+ Coverage   98.70%   99.33%   +0.62%     
==========================================
  Files           6        6              
  Lines         155      151       -4     
==========================================
- Hits          153      150       -3     
+ Misses          2        1       -1     

Impacted Files	Coverage Δ
pennylane_cirq/_version.py	100.00% <100.00%> (ø)
pennylane_cirq/cirq_device.py	100.00% <100.00%> (ø)
pennylane_cirq/simulator_device.py	100.00% <100.00%> (+1.61%)	⬆️

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[antalszava]

Looks awesome, thank you so much @mariaschuld! 😊 The changes related to old QubitDevice methods and the new analytic_probability method would be important, along with removing the attributes that render empty within the docs table (if agreed upon).

Left some suggestions apart from those. At times these refer to multiple places, left a marker at one or two places (these are mostly systematic things).

Also, would it be easy to add a bit of space to the bottom of the page where the Class diagrams are shown? (It's okay if not 😊 )

[antalszava]

The JavaScript formattings seem to be off for CodeFactor 🤔

[josh146]

Have updated the codefactor settings to ignore javascript files!

[mariaschuld]

I think I caught most of your suggestions, and updated to reflect the latest qiskit polish as well.

@josh146 I wonder why CodeFactor still complains about js files?