Browse performance fixes

[alexandrevryghem]

Description

The browse pages currently perform some unnecessary recalculations which cause some performance issues. I updated some Observables to remove useless emits which prevents methods like updatePageWithItems & updatePage from being called twice when switching the sort order for example.

Instructions for Reviewers

List of changes in this PR:

• Prevented unnecessary scope$ emits in ngOnChanges()
• Prevented the updatePageWithItems & updatePage methods from being called twice when you update pagination options or sort direction. This is because the whole combineLatest was triggered twice when making those changes, once by the this.currentPagination$/this.currentSort$ and once by the this.route.queryParams. To fix this I created a new observable routeParams$ for each browse section that doesn't emit when the pagination/sort/... parameters are updated
• Added shareReplay to the requestHref$ observable to BaseDataService's findByHref & findListByHref methods. This will prevent findByHrefs &findListByHrefs who derive their href$ from another Observable call to trigger that Observable over again.

Guidance for how to test or review this PR:

• Verify the browse functionality still works (should also be more performant specifically on larger code bases)
• Add a tap console.log to BrowseService#getBrowseEntriesFor's href$ observable at the end and verify that its creation should be triggered only once
• Add a console.log in both the BrowseByMetadataComponent's updatePage & updatePageWithItems and verify that on first page load it's only called once and it's also only called once when switching the sort order/page size

Checklist

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