[Docs]: Consistent naming of space vs project

### Description

Documentation still references "projects" which is not anymore a notion in the application, replaced by "spaces". We should make sure we use the appropriate notion consistently.

### Location

Everywhere in the documentation.

### Suggestion

_No response_

### Area

Getting started

Search the documentation, especially the Getting started area, for references to "projects" and read each occurrence in context. Update terminology where it refers to the application concept now called "spaces", then review the documentation search results to confirm obsolete references are gone without changing unrelated uses.

Written by the indexing model from the issue text.