ci: Add CodeQL workflow

[luislhl]

Acceptance Criteria

This is the same as https://github.com/HathorNetwork/hathor-explorer-service/pull/222, but including the fixes for the errors reported there.

In this PR there shouldn't be any errors reported.

The fixed errors:

• https://github.com/HathorNetwork/hathor-explorer-service/security/code-scanning/9
• https://github.com/HathorNetwork/hathor-explorer-service/security/code-scanning/3
• https://github.com/HathorNetwork/hathor-explorer-service/security/code-scanning/4
• https://github.com/HathorNetwork/hathor-explorer-service/security/code-scanning/5
• https://github.com/HathorNetwork/hathor-explorer-service/security/code-scanning/6
• https://github.com/HathorNetwork/hathor-explorer-service/security/code-scanning/7
• https://github.com/HathorNetwork/hathor-explorer-service/security/code-scanning/8

Security Checklist

• [ ] Make sure you do not include new dependencies in the project unless strictly necessary and do not include dev-dependencies as production ones. More dependencies increase the possibility of one of them being hijacked and affecting us.