[ECS] [request]: Able to use secrets in TD - Volume - Docker Volume configurations

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**Tell us about your request**
What do you want us to build?
Currently there is no way to pass environment variables as well as secrets to Docker volume configurations
I am trying to Mount Fsx on a linux container using local cifs type mount, but I had to pass clear Text password of Domain User.
We use enterprise tool for managing secrets outside AWS.
It would great if it be referenced similar to Container Environment Variables

It would have been better at-least if we can use something like password=$PASSWORD
and Mount parses it before actually tries mount
Overall, We need mount options to be hidden and not showing up in clear Text

**Which service(s) is this request for?**
This could be Fargate, ECS, EKS, ECR

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
What outcome are you trying to achieve, ultimately, and why is it hard/impossible to do right now? What is the impact of not having this problem solved? The more details you can provide, the better we'll be able to understand and solve the problem.
I am trying to Mount Fsx on a linux container using local cifs type mount, but I had to pass clear Text password of Domain User.

**Are you currently working around this issue?**
How are you currently solving this problem?
Mounting FSx on EC2 as part of User data and referencing mount from container, But this blocks us from moving to FarGate

**Additional context**
Anything else we should know?

**Attachments**
If you think you might have additional information that you'd like to include via an attachment, please do - we'll take a look. (Remember to remove any personally-identifiable information.)

No repository files, tests, or entry points are named. Start by determining whether the request applies to ECS, Fargate, EKS, or ECR and how Docker volume mount options are currently handled. Done means supporting secret-backed mount options without exposing passwords or other sensitive values in clear text.

Written by the indexing model from the issue text.