Deprecate unused methods and classes for initial setup

[joshcanhelp]

Deprecation docblocks and error triggering for unused methods and classes related to initial setup. Also moved all deprecated methods to the bottom of the class.

No functional changes 👍

[codecov-io]

Codecov Report

Merging #550 into master will increase coverage by 0.32%.
The diff coverage is 0%.

@@             Coverage Diff              @@
##             master     #550      +/-   ##
============================================
+ Coverage     15.04%   15.36%   +0.32%     
+ Complexity     1636     1605      -31     
============================================
  Files            71       69       -2     
  Lines          5591     5473     -118     
============================================
  Hits            841      841              
+ Misses         4750     4632     -118

Impacted Files	Coverage Δ	Complexity Δ
...nitial-setup/WP_Auth0_InitialSetup_Connections.php	0% <0%> (ø)	4 <2> (-9)	⬇️

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