Allow password length over 71 chars

Inizia con auth/password/password.go, quindi segui il suo utilizzo da database/database.go e app.go per GOTIFY_DEFAULTUSER_PASS e GOTIFY_DATABASE_CONNECTION. Confronta gli approcci disponibili all'hashing delle password e definisci come vengono gestite le password esistenti; il lavoro sarà completo quando saranno consentite password più lunghe di 71 caratteri senza il panic all'avvio segnalato.

Is your feature request related to a problem? Please describe.
When setting environment variable GOTIFY_DEFAULTUSER_PASS or the password in GOTIFY_DATABASE_CONNECTION to a string longer than 71 chars, I get the following error in my journalctl:

<DATE> <HOSTNAME> systemd[1]: Started podman-gotify.service.
<DATE> <HOSTNAME> <...>[8313]: <...>
<DATE> <HOSTNAME> <...>[8329]: Starting Gotify version 2.6.3@2025-04-27-09:10:38
<DATE> <HOSTNAME> <...>[8329]: panic: bcrypt: password length exceeds 72 bytes
<DATE> <HOSTNAME> <...>[8329]:
<DATE> <HOSTNAME> <...>[8329]: goroutine 1 [running]:
<DATE> <HOSTNAME> <...>[8329]: github.com/gotify/server/v2/auth/password.CreatePassword(...)
<DATE> <HOSTNAME> <...>[8329]:         /src/gotify/auth/password/password.go:9
<DATE> <HOSTNAME> <...>[8329]: github.com/gotify/server/v2/database.New(<...>)
<DATE> <HOSTNAME> <...>[8329]:         /src/gotify/database/database.go:58 +0x469
<DATE> <HOSTNAME> <...>[8329]: main.main()
<DATE> <HOSTNAME> <...>[8329]:         /src/gotify/app.go:42 +0x236
<DATE> <HOSTNAME> <...>[8339]: 2025-05-18 13:23:14.006036461 +0000 UTC m=+0.048855570 container died <...> (image=docker.io/gotify/server:2, name=<...>, PODMAN_SYSTEMD_UNIT=p>
<DATE> <HOSTNAME> <...>[8339]: 2025-05-18 13:23:14.218830403 +0000 UTC m=+0.261649572 container remove <...> (image=docker.io/gotify/server:2, name=<...>, pod_id=<...>>
<DATE> <HOSTNAME> systemd[1]: podman-gotify.service: Main process exited, code=exited, status=2/INVALIDARGUMENT
<DATE> <HOSTNAME> systemd[1]: podman-gotify.service: Failed with result 'exit-code'.
<DATE> <HOSTNAME> systemd[1]: podman-gotify.service: Consumed 610ms CPU time, 19.5M memory peak, 13.3M written to disk.
<DATE> <HOSTNAME> systemd[1]: podman-gotify.service: Scheduled restart job, restart counter is at 5.

This is a thread that describes the problem in detail.

Describe the solution you'd like
I'm not familiar with go and haven't used any of these libraries, but after some research it was often suggested to use argon2id package.

Describe alternatives you've considered

• Implement an environemnt variable/config option to let the user choose the algorithm.
• Add note to config that passwords are limited to 71 UTF-8 chars