Remove configFile URL param support

[kmcginnes]

Description

Removes support for an obscure and undocumented way of loading an initial connection.

To use the feature a user must:

1. Create a valid connection JSON file by exporting from an existing Graph Explorer instance or hand crafting the JSON
2. Put the JSON file in the Graph Explorer source code so it is hosted by the server
3. Launch the Graph Explorer site using the correct param:
   http://localhost:5173/?configFile=connection.json

If those steps are followed then the database will be initialized with the connection data inside the file.

However, if any connections already exist this logic will be skipped. So it is only useful for setting up a brand new user of Graph Explorer.

This process is undocumented and is tedious to set up. There are better approaches to configuring initial connections for new users. So my theory is that this feature was initially created for the original developers to test out new browsers or to quickly setup their test environment after wiping their local database.

Validation

• Verified the feature works, but I have no idea how it was intended to work
• Verified that removing the feature does not break other default connection logic

Related Issues

• Part of Use suspense for app loading process #634
• Resolves [Task] Remove configFile URL param support #726

Check List

• I confirm that my contribution is made under the terms of the Apache 2.0
  license.
• I have run pnpm checks to ensure code compiles and meets standards.
• I have run pnpm test to check if all tests are passing.
• I have covered new added functionality with unit tests if necessary.
• I have added an entry in the Changelog.md.

[kmcginnes]

Updated to fix conflicts