Concepts in hierarchical view are not currently sorted. This PR add functionality to sort concepts by their label according to locale.
Link to relevant issue(s), if any
Part of #1521
Description of the changes in this PR
Sort concepts in hierarchy by label and locale when they are added to hierarchy tree
Addresses requirement 9 in #1521
Known problems or uncertainties in this PR
Concepts are only sorted by label and locale, not notation codes or notation sorting style
Checklist
[ ] phpUnit tests pass locally with my changes
[ ] I have added tests that show that the new code works, or tests are not relevant for this PR (e.g. only HTML/CSS changes)
[ ] The PR doesn't reduce accessibility of the front-end code (e.g. tab focus, scaling to different resolutions, use of .sr-only class, color contrast)
[ ] The PR doesn't introduce unintended code changes (e.g. empty lines or useless reindentation)
Reasons for creating this PR
Concepts in hierarchical view are not currently sorted. This PR add functionality to sort concepts by their label according to locale.
Link to relevant issue(s), if any
Description of the changes in this PR
Sort concepts in hierarchy by label and locale when they are added to hierarchy tree
Addresses requirement 9 in #1521
Known problems or uncertainties in this PR
Concepts are only sorted by label and locale, not notation codes or notation sorting style
Checklist
.sr-only
class, color contrast)