Import/Export feature for tests

BugBug does not currently have an import/export feature for tests. Exporting and importing tests can be very beneficial for users.

By exporting tests, users can save their work and reuse it in other frameworks. This allows users to benefit from further advanced testing without losing their work. Users can also export multiple tests into a single file, which is compatible with many other frameworks (Selenium, Python). The export feature is especially useful to outgrow the capabilities of BugBug.

In addition, users can import tests from other frameworks into BugBug (Selenium, Python). This allows users to reuse their existing test cases and test suites in BugBug. Users can also import multiple tests into BugBug at once, which saves time and effort.