[5.1] Convert mod_languages to service provider

[joomlaweby]

Summary of Changes

Converts the language switcher module to service provider.

Testing Instructions

1. Make sure you have site module mod_languages published
2. You should see module output on frontend

Actual result BEFORE applying this Pull Request

Module works as expected

Expected result AFTER applying this Pull Request

Module works same way as before applying pull request

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed

[ghost]

I have tested this item ✅ successfully on 888f704

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[viocassel]

I have tested this item ✅ successfully on 888f704

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/42929.}

[Quy]

RTC

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/42929.}

[bembelimen]

Thanks