Refactor the configuration and CLI documentation pages

[josh146]

Context:

In #319, the changes were requested for the pages configuration.rst, sf_configuration.rst, and sf_cli.rst. These are described below.

Description of the Change:

• [x] Swap to using command prompt for examples

• [x] Replace cat with type for the command prompt segments

• [x] Standardize the dummy authentication token to AUTHENTICATION_TOKEN, and note everywhere it appears that the user should replace it with their own token

• [x] Refactor the introduction configuration to instead make it focused on the cloud platform. Note: while focusing on the cloud platform, I changed the title to be 'Photonic hardware', so it displays well in the TOC in the sidebar.

• [x] Always put python store account first

• [x] Remove the references to the :func:~.configuration_wizard page.

• [x] In doc/introduction/configuration.rst link to the hardware tutorial

• [x] Specify that the INFILE argument for the CLI is a blackbird script

• [x] Place the corresponding environment variable sentences on newlines

Benefits: suggested changes are incorporated

Possible Drawbacks: Changes requested for the hardware tutorial will be made in a new PR, once this has been merged in.

Related GitHub Issues: #319

[codecov[bot]]

Codecov Report

:exclamation: No coverage uploaded for pull request base (master@e557ba2). Click here to learn what that means. The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #324   +/-   ##
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  Coverage          ?   97.66%           
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  Files             ?       50           
  Lines             ?     6252           
  Branches          ?        0           
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  Hits              ?     6106           
  Misses            ?      146           
  Partials          ?        0

Impacted Files	Coverage Δ
strawberryfields/cli/__init__.py	90.41% <ø> (ø)
strawberryfields/configuration.py	100% <ø> (ø)

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