Fix U4-5194 and U4-5167: Handle multiple spaces and quoted searches in the backoffice correctly

Currently, multiple words result in imprecise search results, because they are not grouped. A search for "John Doe" will result in a search for nodes where the name contains "john" and any field contains "doe". This results in more results when you add multiple words rather than the expected behavior of multiple words narrowing down the search results.
In addition, this pull request also attempts to handle quoted searches correctly. A single quote will cause issues, so single quotes are removed (essentially, quotes are thus ignored until a pair is found).