Optimized siteselector performance

siteselector searched without any delay. While the widget just needs to scan an array, the load
of JavaScript interaction, still, creates quite a significant performance impact which should
not be triggered unless actually necessary.

Change-Id: I4b65beab0f23009819d8fd41de537c0e50d72976
Updated site id input

- $.wikibase.siteselector displays site id only on selecting a site
- Added $.inputautoexpand functionality to site id input

Bug: T76214
Change-Id: I75ca700e08dcd88b00a0c52608f1d083ae485f23
Merge "Optimized siteselector performance"
Merge "Updated site id input"