feat: extending openAPI

[galzunited]

override the defaults with custom openAPI - self hosted css for future changes. as for now, refactored some of the apis and added new one so we could create user/events manually. excluded irrelevant apis from schema.

[codecov-io]

Codecov Report

Merging #226 (9dbc02b) into develop (cec69ea) will decrease coverage by 0.31%. The diff coverage is 89.41%.

@@             Coverage Diff             @@
##           develop     #226      +/-   ##
===========================================
- Coverage    99.04%   98.73%   -0.32%     
===========================================
  Files           59       60       +1     
  Lines         2625     2687      +62     
===========================================
+ Hits          2600     2653      +53     
- Misses          25       34       +9     

Impacted Files	Coverage Δ
app/routers/calendar.py	100.00% <ø> (ø)
app/routers/categories.py	96.55% <71.42%> (-3.45%)	:arrow_down:
app/routers/user.py	91.11% <80.00%> (-8.89%)	:arrow_down:
app/main.py	92.85% <81.81%> (-4.12%)	:arrow_down:
app/utils/extending_openapi.py	88.88% <88.88%> (ø)
app/routers/agenda.py	100.00% <100.00%> (ø)
app/routers/dayview.py	100.00% <100.00%> (ø)
app/routers/event.py	97.88% <100.00%> (+0.19%)	:arrow_up:
app/routers/invitation.py	100.00% <100.00%> (ø)
app/routers/profile.py	92.07% <100.00%> (ø)
... and 4 more

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[yammesicka]

Please solve the conflicts :)

[yammesicka]

I've fixed some conflicts in order to merge, but there are some errors - please have a look and fix it :)

https://github.com/PythonFreeCourse/calendar/pull/226/checks?check_run_id=1896171413