feat: Added functionality to allow T-SQL agent job steps

[GooseLF]

So I done some things and some stuff.

• .pre-commit-config.yaml
  • Commented out Safety until they fix their thing ('NoneType' object has no attribute 'telemetry' Lucas-C/pre-commit-hooks-safety#29)
• src/deploy.py
  • Updated deploy_ssis() to accommodate T-SQL SQL agent job steps
• src/model.py
  • Made Step.package optional
  • Added Step.sql_string as an optional field
  • Added Step.retry_attempts as an optional field
  • Added Step.retry_interval as an optional field
  • Added Step.post_init() to ensure the correct field, either package or sql_string is set for the correct step type, SSIS or T-SQL respectively
• src/sql/agent/create_job_step.sql
  • Added retry_attempts and retry_interval parameters
• src/sql/agent/create_job_step_using_proxy.sql
  • Added retry_attempts and retry_interval parameters
• src/sql/db.py
  • Added method for creating a SQL Agent Job Step with a T-SQL Subsystem
  • Added retry_interval and retry_attempts to both SSIS and T-SQL Subsystem step methods
• test/test_model.py
  • Added unit tests for new functionality

Closes #39.

#40 should be done in a separate PR once this PR is merged so we know what we've got to refactor.

[github-actions]

Unit Test Results

44 tests  +3   43 ✔️ +3   0s ⏱️ ±0s
  1 suites ±0     1 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit 29e8557. ± Comparison against base commit 4f11225.

♻️ This comment has been updated with latest results.

[gvee-uk]

Few initial comments before local testing.