Expand the Options for storing the sensitive parameters to include binary secrets and SSM Parameter Store

[ChrisPates]

Is your feature request related to a problem? Please describe.
Currently sensitive configuration data must be stored in AWS Secrets Manager secrets, however for some customers using SSM Parameter Store may be sufficient (since they do not need cross account/cross region support) and wish to reduce the operating cost of the SSOSync deployment.

Describe the solution you'd like
Add detection for and support of SSM parameter store secrets and binary secrets in Secrets Manager.

Additional context
Requests originally raised under the following issues:

• SSOSync fails to get binary secrets #130
• Allow use of Systems Manager Parameters instead of Secrets Manager Secrets #93

[dancorne]

Hey @ChrisPates, I'd opened #130 because it looked like binary secrets should work, however I believe the logic is buggy there. It was easy enough for us to switch to a string secret to fix our syncing, but also the bugfix is fairly trivial so thought I'd open a PR. If you've got wider refactoring plans for this code this might not be needed though, happy to close that PR off if so.

[ChrisPates]

So other folk have expressed a desired for SSM Parm-store support and even raw env Vars.  Leave the PR for now, I’ll have a look and it may still be used as part of the broader piece of work.