Add feishu webhook support

[lunny]

This PR will add webhook support for feishu(https://feishu.cn).

[codecov-io]

Codecov Report

Merging #10229 into master will decrease coverage by 0.08%.
The diff coverage is 3.22%.

@@            Coverage Diff             @@
##           master   #10229      +/-   ##
==========================================
- Coverage   43.67%   43.58%   -0.09%     
==========================================
  Files         582      583       +1     
  Lines       80047    80263     +216     
==========================================
+ Hits        34961    34986      +25     
- Misses      40751    40945     +194     
+ Partials     4335     4332       -3

Impacted Files	Coverage Δ
modules/structs/hook.go	6.66% <ø> (ø)	⬆️
modules/webhook/webhook.go	43.6% <0%> (-1.71%)	⬇️
models/webhook.go	68.7% <0%> (-0.48%)	⬇️
modules/webhook/feishu.go	0% <0%> (ø)
modules/auth/repo_form.go	44.44% <0%> (-0.78%)	⬇️
routers/repo/webhook.go	1.27% <0%> (-0.11%)	⬇️
modules/setting/webhook.go	56.25% <100%> (ø)	⬆️
routers/routes/routes.go	86.57% <100%> (+0.09%)	⬆️
modules/queue/unique_queue_disk_channel.go	52.56% <0%> (-1.93%)	⬇️
... and 5 more

---

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[6543]

need update too:

gitea/modules/structs/hook.go

Line 44 in ad2642a

// enum: dingtalk,discord,gitea,gogs,msteams,slack,telegram

[6543]

i think you missed to change some things where you copy parts of the code ...

[lunny]

@6543 @guillep2k done.