feat_: graceful shutdown with status-backend

[igor-sirotin]

1. This is just common sense to do
2. It's required for functional tests, because coverage data is only saved correctly with graceful shutdown of the app
3. Added support for SIGTERM
   For statusd we only support SIGINT, so I had to change the emitted signal. We won't need to do it for status-backend.
   

   status-go/tests-functional/docker-compose.test.status-go.yml

   Line 28 in 35dc84f

   stop_signal: SIGINT

[status-im-auto]

Jenkins Builds

❔	Commit	#️⃣	Finished (UTC)	Duration	Platform	Result
✔️	2e8b593	#1	2024-12-10 16:49:51	~4 min	linux	📦zip
✔️	2e8b593	#1	2024-12-10 16:51:04	~5 min	windows	📦zip
✔️	2e8b593	#1	2024-12-10 16:51:07	~6 min	android	📦aar
✔️	2e8b593	#1	2024-12-10 16:51:15	~6 min	ios	📦zip
✔️	2e8b593	#1	2024-12-10 16:51:48	~6 min	tests-rpc	📄log
✔️	2e8b593	#1	2024-12-10 16:52:25	~7 min	macos	📦zip
✔️	2e8b593	#1	2024-12-10 16:56:22	~11 min	macos	📦zip
✔️	2e8b593	#1	2024-12-10 17:16:05	~30 min	tests	📄log
✔️	7132d47	#2	2024-12-10 16:55:55	~3 min	windows	📦zip
✔️	7132d47	#2	2024-12-10 16:56:34	~4 min	linux	📦zip
✔️	7132d47	#2	2024-12-10 16:58:06	~6 min	android	📦aar
✔️	7132d47	#2	2024-12-10 16:58:07	~6 min	tests-rpc	📄log
✔️	7132d47	#2	2024-12-10 16:58:42	~6 min	ios	📦zip
✔️	7132d47	#2	2024-12-10 16:59:53	~7 min	macos	📦zip
✔️	7132d47	#2	2024-12-10 17:06:28	~9 min	macos	📦zip
✔️	7132d47	#2	2024-12-10 17:46:45	~30 min	tests	📄log

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 61.35%. Comparing base (e7cc535) to head (7132d47).
Report is 7 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #6189      +/-   ##
===========================================
+ Coverage    60.94%   61.35%   +0.41%     
===========================================
  Files          832      832              
  Lines       109875   109884       +9     
===========================================
+ Hits         66962    67421     +459     
+ Misses       35074    34572     -502     
- Partials      7839     7891      +52     

Flag	Coverage Δ
functional	19.55% <100.00%> (+5.65%)	⬆️
unit	60.03% <ø> (-0.04%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
cmd/status-backend/main.go	86.11% <100.00%> (+86.11%)	⬆️

... and 63 files with indirect coverage changes