DynamoDB local installation not being retained

**Actual Behaviour**

The dynamodb local install doesn't seem to be retained and I have to re-run the command `serverless dynamodb install` every so often.

**Expected Behaviour**

The dynamodb local should be retained.

**Steps to reproduce it**

`yarn add` any module

**Would you like to work on the issue?**

I am able to look into this if I knew where dynamodb is being installed locally and try to determine what is deleting it.

Start by locating the installation path and handling behind the `serverless dynamodb install` command, then reproduce the issue by running `yarn add` on a project with DynamoDB Local installed. Done means the DynamoDB Local installation remains available after adding another module and does not require reinstalling.

Written by the indexing model from the issue text.