Allow us to use partial matching in code/repository search

After implementing BSERV-3854, we can use substrings for code/repository search.

For example,

• We can find repositories like "apple banana", "banana cat" with a keyword "banana"
• We can find methods like "appleBanana", "bananaCat" in codes with a keyword "banana"

However, in some cases, we want to search them in the following way.

• Search functions like "applebanana", "bananacat" in codes with a keyword "banana"

At this moment, Bitbucket Server doesn't allow us to do search in that way.

I'd appreciate if you guys would consider this partial matching feature.
Additionally, when implementing this feature, please apply the fix not only to English but also to other languages containing multibyte characters as well.

Regards,
Yuki