[FEATURE] Deprecate ssh-rsa format

[bhrg3se]

Describe the feature:

Replace ssh-rsa with rsa-sha2-256/512 or ssh-ed25519

Describe why this feature is needed:

Since openSSH has deprecated open-ssh format, there will be issues with new openSSH servers/clients.

Scope of feature:

• [ ] TRASA codebase
• [ ] dashboard
• [x] server
• [ ] mobile app
• [ ] browser extension
• [ ] device agent
• [ ] website/docs