docs: update troubleshooting to reflect merge in argo-cd and add map examples in services

[Sayrus]

This follows questions asked on #argo-cd-notifications:

• It is not always clear whether the map keys are defined by ArgoCD or defined by the user. This small update aims to add example to ensure the information is clearer to the user. (If merged, generated docs will need an update: https://github.com/argoproj/notifications-engine/pull/104)
• The troubleshooting page has a procedure for when argocd-notifications was not merged into argo-cd. The binary location is wrong and the ability to execute the client from the new image is not available.

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Checklist:

• [X] Either (a) I've created an enhancement proposal and discussed it with the community, (b) this is a bug fix, or (c) this does not need to be in the release notes.
• [X] The title of the PR states what changed and the related issues number (used for the release note).
• [ ] I've included "Closes [ISSUE #]" or "Fixes [ISSUE #]" in the description to automatically close the associated issue.
• [ ] I've updated both the CLI and UI to expose my feature, or I plan to submit a second PR with them.
• [X] Does this PR require documentation updates?
• [X] I've updated documentation as required by this PR.
• [ ] Optional. My organization is added to USERS.md.
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[codecov[bot]]

Codecov Report

Base: 45.76% // Head: 45.76% // No change to project coverage :thumbsup:

Coverage data is based on head (6ad67d4) compared to base (e53ab49). Patch has no changes to coverable lines.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #10589   +/-   ##
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  Coverage   45.76%   45.76%           
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  Files         236      236           
  Lines       28519    28519           
=======================================
  Hits        13053    13053           
  Misses      13661    13661           
  Partials     1805     1805           

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[todaywasawesome]

Closing for not really being relevant any longer. Feel free to reopen if you want to take up the cherry-pick option.