Invenio-search-ui

- Fix web accessibility issue.

- Upgrade react-overridable dependency.

- Add namespace based on `config.appId` passed from DOM.
- Enable multiple search application support. Introduces a new parameter in
`utils.createSearchAppInit(...)` called `multi` that allows users to override
each application's components using `appId` as a prefix.
- Bump semantic-ui-react to latest release
- Adds `semantic-ui-react/css-patch` because of https://github.com/Semantic-Org/Semantic-UI/issues/7073

- Pass search config in overridable `SearchApp.layout`

- Make sortOptions available when overriding Results component
- Align pagination to center

- SearchApp refactoring
- Standardize and document configuration
- Improve reusability and customization for other modules
- Split into smaller overridable components
- Make default searchbar overridable
- Make sort configurable
- Add configuration to disable sort order
- Pass backend agg to aggregation component
- Bump React-SearchKit JS version.
- Adds React-SearchKit JS application for use with Semantic UI theme.
- Adapt to latest React-SearchKit changes.
- Migrate CI to GitHub actions.
- Fixes metadata path in AngularJS template.
- Moves AngularJS files in correct path.