refactor(agent-manager): remove gzip middleware, update TLS configura…

[osmontero]

This pull request updates the TLS configuration and error handling in the agent-manager/updates/updates.go file to improve security and reliability. It also removes gzip middleware from the Gin server setup.

TLS configuration improvements:

• Expanded the list of supported cipher suites to include both RSA and ECDSA key exchanges, added support for TLS 1.3, and set preferred elliptic curves for better security. (agent-manager/updates/updates.go)
• Set both minimum and maximum TLS versions (MinVersion: tls.VersionTLS12, MaxVersion: tls.VersionTLS13) for stricter protocol enforcement. (agent-manager/updates/updates.go)

Error handling improvements:

• Updated error logging to ignore the return value from catcher.Error and added a 5-second delay before exiting if TLS credentials fail to load, which may help with debugging or orchestrator restarts. (agent-manager/updates/updates.go) [1] [2]

Middleware changes:

• Removed the gzip middleware from the Gin server, so HTTP responses are no longer compressed with gzip by default. (agent-manager/updates/updates.go) [1] [2]