feat: federated calendar sharing

[st3iny]

Requires nextcloud/server#54127

[codecov]

Codecov Report

❌ Patch coverage is 16.00000% with 21 lines in your changes missing coverage. Please review.
✅ Project coverage is 14.84%. Comparing base (9a754e6) to head (d08a9ba).
⚠️ Report is 117 commits behind head on main.

Files with missing lines	Patch %	Lines
.../AppNavigation/EditCalendarModal/SharingSearch.vue	0.00%	15 Missing ⚠️
...ents/AppNavigation/EditCalendarModal/ShareItem.vue	0.00%	5 Missing ⚠️
src/store/calendars.js	0.00%	1 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (9a754e6) and HEAD (d08a9ba). Click for more details.

HEAD has 4 uploads less than BASE

Flag	BASE (9a754e6)	HEAD (d08a9ba)
php	4	0

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #6998      +/-   ##
============================================
- Coverage     22.98%   14.84%   -8.14%     
============================================
  Files           254      212      -42     
  Lines         12589    10299    -2290     
  Branches       2478     2484       +6     
============================================
- Hits           2893     1529    -1364     
+ Misses         9346     8420     -926     
  Partials        350      350              

Flag	Coverage Δ
javascript	14.84% <16.00%> (+<0.01%)	⬆️
php	?

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[st3iny]

I squashed all commits and added a simple feature gate to prevent an additional request for remote sharees.