feat(policies): add rails sessions policy

[elsapet]

Description

• Add support for Rails' leaking sessions policy
• Some changes to detectors to support assignment node types (which can have anything - identifier, hash, etc - on the right hand side) -- thanks @vjerci for the help on this 🙏

Sample code:

class Users < ApplicationRecord
  session[:user_name] = "mish"
  session[:current_user] = user.first_name
end

Policy report

Policy Report

=====================================
Policy list:

- Session leaking
- Application level encryption missing
- Logger leaking


CRITICAL: Session leaking policy breach with Personal data
Session leaks detected

File: ../../Desktop/example/user.rb:4

 4 session[:current_user] = user.first_name

=====================================

Policy breaches detected

3 policies were run and 1 breaches were detected.

CRITICAL: 1 (Session leaking)
HIGH: 0
MEDIUM: 0
LOW: 0


exit status 1

Checklist

• I've added test coverage that shows my fix or feature works as expected.
• I've updated or added documentation if required.
• I've included usage information in the description if CLI behavior was updated or added.
• PR title follows Conventional Commits format

[swarmia]

✅  Linked to AMA-3274 · Session Leaking
➡️  Part of AMA-3273 · Ruby Policies
➡️  Part of AMA-2947 · OSS - Curio CLI

[cfabianski]

What do you think?