feat!: Update default values for security posture improvement

[bryantbiggs]

Description

• update outputs to use try() function
• update default settings for passwords to fix security settings
  • do not set an empty string as default (ref Tfsec says there is a critical vulnerability in variables.tf #354)
  • change default behavior to use randomly generated password of length 16 (was 10 previously)
• update default settings to enable encryption by default (ref Tfsec says there is a critical vulnerability in variables.tf #354)
• set username, password, and engine to null when a replicate_source_db or snapshot_identifier is provided; these values are already provided in the respective source (ref Fix: RDS Read Replica - Do not create random password module is created as a read replica #324)
• add new attribute replica_mode and bump AWS provider version to support (ref Feat/add replica mode argument #357)
• add latest_restorable_time to ignored changes (ref feat: Added latest_restorable_time to ignore_changes #356)
• correct db_subnet_group_name to use full name when prefix is enabled (ref fix: Add full subnet group name when prefix is enabled #359)
• add restore_to_point_in_time attribute to MSSQL instance (ref Feat: RDS SQL Server instance engine restore_to_point_in_time support #363)
• bump min supported version of Terraform to 0.13.1
• bump random provider to be consistent using v4.x due to name being deprecated and db_name replacing it

For complete list of changes, please see upgrade guide https://github.com/bryantbiggs/terraform-aws-rds/blob/feat/updates/UPGRADE-4.0.md

Motivation and Context

• Closes feat: control log group and stream #105
• Closes Fix: RDS Read Replica - Do not create random password module is created as a read replica #324
• Closes Tfsec says there is a critical vulnerability in variables.tf #354
• Closes feat: Added latest_restorable_time to ignore_changes #356
• Closes Feat/add replica mode argument #357
• Closes fix: Add full subnet group name when prefix is enabled #359
• Closes restore_to_point_in_time for RDS SQL Server instance engine #362
• Closes Feat: RDS SQL Server instance engine restore_to_point_in_time support #363
• Closes Oracle DB ReplicaMode Support #373
• Closes feat: Argument name is deprecated in AWS provider v4, using db_name instead #374
• Closes "engine" conflicts with "replicate_source_db" in hashicorp/aws 4.0.0 #377

Breaking Changes

• Yes

How Has This Been Tested?

• I have tested and validated these changes using one or more of the provided examples/* projects

[bryantbiggs]

@antonbabenko ps - it looks like their might be an issue with the token or something on the PR title check for this repo, not sure Error: Resource not accessible by integration

[antonbabenko]

@antonbabenko ps - it looks like their might be an issue with the token or something on the PR title check for this repo, not sure Error: Resource not accessible by integration

I am not sure what can be the reason for this. I have not touched anything, it uses the default GITHUB_TOKEN. Probably some issues on the GitHub side.

[antonbabenko]

This PR is included in version 4.0.0 🎉

[github-actions]

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