[full-ci] flush all the build cache

[prashant-gurung899]

Description

This PR adds the following pipelines to purge the cache of browsers, playwright-tracing-results and opencloud-build:

• purge-browser-build-cache
• purge-playwright-tracing-cache
• purge-opencloud-build-cache

Check these previous CIs to see the cache being deleted:

• browser-cache: https://ci.opencloud.eu/repos/6/pipeline/2271/176 (Pipeline's name is not updated here.)
• playwright-tracing-results: https://ci.opencloud.eu/repos/6/pipeline/2286/179
• opencloud-build: https://ci.opencloud.eu/repos/6/pipeline/2261/175

Related Issue

• Related to: flush all caches in web CI qa#51

How Has This Been Tested?

• 🤖

Types of changes

• Bugfix
• Enhancement (a change that doesn't break existing code or deployments)
• Breaking change (a modification that affects current functionality)
• Technical debt (addressing code that needs refactoring or improvements)
• Tests (adding or improving tests)
• Documentation (updates or additions to documentation)
• Maintenance (like dependency updates or tooling adjustments)

[Copilot]

Pull Request Overview

This PR adds new pipelines to purge various caches—specifically for Opencloud build, browsers, and playwright tracing—to improve the cleanup process after builds.

• Updated the afterPipelines function to include purge functions for Opencloud build, browser, and tracing caches.
• Refactored cache purging by replacing genericCachePurge with a more generic purgeCache function that accepts an additional flush_age parameter.
• Introduced dedicated purge functions for Opencloud build, browser, and tracing caches.

Comments suppressed due to low confidence (3)

.woodpecker.star:247

• Consider adding inline comments that explain the order and purpose of each cache purge function added here to help future maintainers understand the cache clearing sequence.

    return publishRelease(ctx) + [purgeBuildArtifactCache(ctx), purgeOpencloudBuildCache(ctx), purgeBrowserCache(ctx), purgeTracingCache(ctx)]

.woodpecker.star:1187

• Verify that the pipeline executor accepts a dictionary for the 'steps' field instead of a list, as used in previous implementations. If this change is intentional, consider adding a brief comment outlining the rationale for future reference.

        "steps": {

.woodpecker.star:1209

• Double-check that the hardcoded flush path 'cache/opencloud-eu/web' is intentional and aligns with the desired cache location for build artifacts, especially in comparison to other purge functions.

        return purgeCache("purge_build_artifact_cache", "cache/opencloud-eu/web", 1)