Establish a "Workspaces" section in user settings
MR: Pending
## Description
### Problem
For a couple of upcoming features and configuration options we will need to allow users to set their individual preferences for Remote Development workspaces:
* Timeout period
* Variables
* Editor (VS Code, JetBrains, ...)
We already enable users to set necessary configuration for Remote Development on the group level in a "Workspaces" section in the group settings:
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### Solution
Just like we already have on the Group settings level, we should have a "Workspaces" section in the User settings.
The initial setting used to drive this feature will be `project_cloner_image`, for users that may need to have custom control over how they clone their repos (there have already been some requests for this).
### Links
- See https://gitlab.com/groups/gitlab-org/-/epics/14186+ for overview and more context
- See [Related Issues and MRs section in that epic](https://gitlab.com/groups/gitlab-org/-/epics/14186#related-issues-and-mrs) for related issues and MRs
## Acceptance Criteria
- [ ] Add UserSettings step to the Workspaces Settings Module
- [ ] Add new section in User settings. Should behave similar to settings for Agent and Cascading Settings levels, which will be added as part of https://gitlab.com/groups/gitlab-org/-/epics/14186+
## Technical Requirements
Add UserSettings step to the Workspaces Settings Module:
* This will involve adding a new UserSettings step to the Workspaces ROP Settings Module chain
* This step will observed the `locked` flag for each relevant setting, just as we previously added for `lib/remote_development/settings/current_settings_reader.rb`.
## Design Requirements
issue