* Remove a special queued experiments
fix#6157
1. dvc exp remove not accept queued experiments name
2. add some tests for this feature
* Extract tests and add revision support
1. Extract remove experiments to a new file.
2. revision can be used to remove special queued experiment
* Accept shortened revisions
* Split removing committed and queued exp functions
* Api name change
* Return to the old API name
* shorten some functions
* Error message change
* Better test cases, more corner case
* Still raise exception in a mixed case
