Remove dedicated Microsoft integration user

[mickmister]

Summary

This PR removes the bot account from the OAuth process. The application level permissions work the exact same way as before.

Calls to GetSchedule are now adjusted to one user's schedule, to have access to the user's event details.

Ticket Link

Fixes #75

[larkox]

LGTM, just one comment and one question.

[larkox]

LGTM

[DHaussermann]

@mickmister I started over with a fresh server and tested an install without a bot.
Seems like everything works fine except 2 command...

/mscalendar viewcal
/mscalendar summary view

They produce the following error: msg":"Unable to execute command.","path":"/api/v4/commands/execute","request_id":"zzex7xgc8p8qdydunaunguto3e","ip_addr":"...","user_id":"g1a5x4iu9f883gmbwgemdxh6ch","method":"POST","err_where":"mscalendarplugin.ExecuteCommand","http_code":500,"err_details":"Command /mscalendar summary failed: 403 Forbidden: {\"error\":{\"code\":\"ErrorAccessDenied\",\"message\":\"Access is denied. Check credentials and try again.\"}}"}

All other slash commands seem to work fine.

If this is related to a bot-less install, possibly there is an update needed to how permissions are configured. Thoughts?

Also Please remove Step 3: Configure Bot Account from the read-me.

[mickmister]

@DHaussermann I'm unable to reproduce the issues with /mscalendar viewcal and
/mscalendar summary view on a fresh install. I've removed the bot account instructions from the README.

[codecov-io]

Codecov Report

Merging #76 into master will decrease coverage by 2.71%.
The diff coverage is 50.81%.

@@            Coverage Diff             @@
##           master      #76      +/-   ##
==========================================
- Coverage   25.31%   22.59%   -2.72%     
==========================================
  Files          61       61              
  Lines        2303     2248      -55     
==========================================
- Hits          583      508      -75     
- Misses       1654     1682      +28     
+ Partials       66       58       -8     

Impacted Files	Coverage Δ
server/command/command.go	29.41% <ø> (-3.93%)	⬇️
server/command/connect.go	100.00% <ø> (ø)
server/command/disconnect.go	100.00% <ø> (ø)
server/mscalendar/user.go	5.26% <ø> (-14.33%)	⬇️
server/remote/msgraph/remote.go	4.54% <0.00%> (-1.34%)	⬇️
server/mscalendar/filters.go	28.94% <12.50%> (-13.56%)	⬇️
server/remote/msgraph/get_schedule_batched.go	40.00% <59.25%> (-11.67%)	⬇️
server/mscalendar/availability.go	46.36% <100.00%> (+0.34%)	⬆️
server/mscalendar/client.go	28.57% <100.00%> (-31.43%)	⬇️
server/mscalendar/oauth2.go	86.79% <100.00%> (-2.44%)	⬇️
... and 3 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a4cd92a...e6174ce. Read the comment docs.

[DHaussermann]

Tested and passed.

• Tested install without bot service user
• Ran through brief regression testing
• Issues found above were due to mis-configured Azure app permissions (Future doc change coming to clarify this) The issue where unrelated to bot removal.
• No other issues found
  LGTM! Thanks @mickmister