[Workflows] Add `Go` Lint check and Security Checks

[sthanikan2000]

Problem

There is no workflow available for the code quality checks. Even though we can enable CodeQL check at settings, it is resource consuming and run per every push to the PR branches.

Proposed Solution

Add the following to the github workflows:

• golangci-lint
• gosec

Alternatives

No response

[ginaxu1]

Nayana: need pre-submit check too

[ginaxu1]

Proposed Changes

First, create .golangci.yml, a config file for golangci-lint at the root of the repository.

• Enable standard linters: govet, staticcheck, gosec, gosimple, unused, ineffassign, typecheck.
• Configure gosec rules (excluding some noisy ones if necessary, but starting strict).

Then, update the validation workflows for each Go service to include golangci-lint and gosec steps

Testing

1. automated - the next PR created will trigger these checks
2. manual verification

make quality-check portal-backend // or any service in opendif-core