CVAT new UI: find the way to simplify the syntax for filters

[aschernov]

My actions before raising this issue

• Read/searched the docs
• Searched past issues

Expected Behaviour

The variety of filters should be visually and manually easy and quick to use. Without difficult syntax and with flexible opportunities to quickly correct or change them.

Current Behaviour

1. The syntax for simple labels became harder to write. For example:
   before: vehicle after: label =="vehicle"
2. There is no way to correct a filter if we made some mistake. We can only delete that we wrote before and write a filter from the beginning again:
   

Possible Solution

Simplify the syntax. Add the opportunity to change symbols in previous filters. Create a comfortable for using panel of filters.

Context

We spend much time to understand how to use some filters correctly and how to write them. Not all users can do it. It influences the validation process.