Inconsistent capitalization of createUIDefinition.json/createUiDefinition.json

### Issue Details

Trying to run sideload-createuidef.sh on demos/100-marketplace-sample with a case-sensitive filesystem:

```
?1 100-marketplace-sample $ ../../sideload-createuidef.sh -a . my-offer
Checking for storage account...
WARNING:
There are no credentials provided in your command and environment, we will query for account key for your storage account.
It is recommended to provide --connection-string, --account-key or --sas-token in your command as credentials.

You also can add `--auth-mode login` in your command to use Azure Active Directory (Azure AD) for authorization if your login account is assigned required RBAC roles.
For more information about RBAC roles in storage, visit https://docs.microsoft.com/en-us/azure/storage/common/storage-auth-aad-rbac-cli.

In addition, setting the corresponding environment variables can avoid inputting credentials in your command. Please use --help to get more information about environment variable usage.
ERROR: [Errno 2] No such file or directory: './createUIDefinition.json'
Please check the file path.
```

createUiDefinition.json is referenced throughout the project with use of both createUiDefinition.json and createUIDefinition.json throughout. Why not standardize on one capitalization so that scripts are not broken on case-sensitive filesystems?
### Repro steps (*if necessary, delete otherwise*)
1. cd demos/100-marketplace-sample
2. ../../sideload-createuidef.sh -a . my-offer

Start with sideload-createuidef.sh and the demos/100-marketplace-sample directory, then search the project for both createUIDefinition.json and createUiDefinition.json spellings. Standardize the references and filename capitalization consistently, and confirm that sideload-createuidef.sh -a . my-offer works on a case-sensitive filesystem.

Written by the indexing model from the issue text.