Update themes documentation & CI

[rickstaa]

Is your feature request related to a problem? Please describe.

To streamline maintenance processes, we've temporarily halted the addition of new themes (details can be found here). While this adjustment is in effect, it's crucial to effectively communicate this change to our users and update the CI accordingly.

Describe the solution you'd like

To ensure utmost transparency with this change, we propose the following steps:

• Update CONTRIBUTING.md to inform contributors of the change docs(contributing): themes addition paused #3408.
• Update README.md to notify users of the temporary pause in new theme additions docs: themes addition paused #3409.
• Disable preview-theme.yml.
• Disable stale-theme-pr-closer.yaml.
• Implement a new action that automatically closes new theme pull requests and provides an explanatory message. See stale-theme-pr-closer.yaml for an example.
• Disable top-themes section in top-issues-dashboard.yml.

Describe alternatives you've considered

No alternatives have been considered at this time.

Additional context

No additional information provided.

[qwerty541]

@rickstaa I think that it's good decision to temporary halt themes addition, since it's prevent wasting our time on a lot of spam pull requests. I only want you to review two my pull requests before (#3401 and #3400), recently i did a little work to allow users contribute gradient themes and i don't want the result of my work to be lost, since it would be userful if we're going to enable back themes addition in future.

[rickstaa]

@rickstaa I think that it's good decision to temporary halt themes addition, since it's prevent wasting our time on a lot of spam pull requests. I only want you to review two my pull requests before (#3401 and #3400), recently i did a little work to allow users contribute gradient themes and i don't want the result of my work to be lost, since it would be userful if we're going to enable back themes addition in future.

Of course! Great additions if we enable the theme contributions in the future. I merged your PRs into the main branch!

[qwerty541]

@rickstaa I think that it's good decision to temporary halt themes addition, since it's prevent wasting our time on a lot of spam pull requests. I only want you to review two my pull requests before (#3401 and #3400), recently i did a little work to allow users contribute gradient themes and i don't want the result of my work to be lost, since it would be userful if we're going to enable back themes addition in future.

Of course! Great additions if we enable the theme contributions in the future. I merged your PRs into the main branch!

Thanks! Looks like i made a mistake while implementing feature to allow addition of gradient themes and preview-theme workflow still fails. I have opened pull request #3427 to resolve this issue, please check it.