LPD-70440 Add client-extensions folder

[kyle-miho]

https://liferay.atlassian.net/browse/LPD-70440

[kyle-miho]

Ticket / linked slack message didnt provide any info on where the folder should be located, but I can make a quick fix if this is the wrong directory location

[drewbrokke]

@kyle-miho thanks for sending this. The client-extensions folder needs to live in the root of the Workspace rather than in the configs folder, since we want a place where Client Extensions can be built from source. We want that part of the structure to be similar to what is seen in the liferay-sample-workspace from portal.

If you put CX source code in configs/common/client-extensions, then the source code would be copied into the Docker container without being built.

One you adjust the structure, you can test it by copying one of the client extensions from the liferay-sample-workspace into the new client-extensions folder and starting up with lec start. You should observe the Workspace build and deploy the change.