Fixes#22714
### Changes:
1. Add a token filter which named "camelCase" between custom unicode
token filter and "to_lower" token filter when add custom analyzer.
### Notice:
If users want this feature to work, they should delete folder under
{giteaPath}/data/indexers and restart application. Then application will
create a new IndexMapping.
### Screenshots:
![image](https://user-images.githubusercontent.com/33891828/217715692-c18c41f2-57a1-4727-861c-470935c8e0c8.png)
### Others:
I originally attempted to give users the ability to configure the
"token_filters" in the "app.ini" file. But I found that if users does
not strictly follow a right order to register "token_filters", they
won't get the expected results. I think it is difficult to ask users to
do this. So I finally give up this idea.
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Co-authored-by: Jason Song <i@wolfogre.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>