Improve App initialization error logs + docs

[srajiang]

Summary

• Improves App initialization error case logging
• Adds links to relevant documentation for better troubleshooting
• Tweaks OAuth documentation to specify required oauth installer options.
• Additions to help improve code readability make maintaining easier

Test

• Easiest way would be to use npm link these changes to one of your sample apps and try out different combos of App options.

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

Merging #1250 (990cd48) into main (2a97007) will not change coverage.
The diff coverage is 77.77%.

@@           Coverage Diff           @@
##             main    #1250   +/-   ##
=======================================
  Coverage   73.22%   73.22%           
=======================================
  Files          17       17           
  Lines        1438     1438           
  Branches      431      431           
=======================================
  Hits         1053     1053           
  Misses        300      300           
  Partials       85       85           

Impacted Files	Coverage Δ
src/App.ts	85.05% <77.77%> (ø)

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[seratch]

Left one comment about the change on the boolean test part. All other changes sound great 👍

[mwbrooks]

Nice improvement on clarity. I always appreciate when arguments are explicitly "required" or "optional"

[filmaj]

Sorry I'm late to the party here! Agree with the comments here, there are a few small tweaks left to some of the wording and error messaging that would improve this PR. That being said, thanks for putting the time into making these changes - already a huge improvement over what was there before!