feat: use the metadata with correct language

[pcg-kk]

feat: provide a language support for community pages

References

Add references/links to any related issues or PRs. These may include:

• Fixes #2056
• Requires DSpace/DSpace#9610 (if a REST API PR is required to test this)

Description

In this PR we provide an mechanism to upload more than one language for communities and collections pages. User can define a page in all supported by DSpace languages from an customer environment file.

Instructions for Reviewers

Please add a more detailed description of the changes made by your PR. At a minimum, providing a bulleted list of changes in your PR is helpful to reviewers.

List of changes in this PR:

• We provide an form to save multiple languages
• We changed a way to display texts from specific languages
• We modify the backend API to save more than one metadata for each type

Include guidance for how to test or review your PR. This may include: steps to reproduce a bug, screenshots or description of a new feature, or reasons behind specific changes.

Checklist

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• [x] My PR is small in size (e.g. less than 1,000 lines of code, not including comments & specs/tests), or I have provided reasons as to why that's not possible.
• [x] My PR passes ESLint validation using yarn lint
• [x] My PR doesn't introduce circular dependencies (verified via yarn check-circ-deps)
• [x] My PR includes TypeDoc comments for all new (or modified) public methods and classes. It also includes TypeDoc for large or complex private methods.
• [x] My PR passes all specs/tests and includes new/updated specs or tests based on the Code Testing Guide.
• [x] If my PR includes new libraries/dependencies (in package.json), I've made sure their licenses align with the DSpace BSD License based on the Licensing of Contributions documentation.
• [x] If my PR includes new features or configurations, I've provided basic technical documentation in the PR itself.
• [x] If my PR fixes an issue ticket, I've linked them together.