Search (in admin) does not work if keyword smaller than 3 chars
### Describe the bug
When searching for podcast episodes in the podcast admin page, the search does not return anything if the keyword is 1 or 2 characters. This could be an expected behaviour, but it is not explicit
### Steps to reproduce
0. Have podcast episodes and go to the episode list
1. Search for a two-letter word
### Expected behavior
A list of episodes containing this two-letter word, or a message saying that we can't search for words smaller than 3 letters, either before or after the search.
### Actual behavior
No result found.
### Relevant logs and/or screenshots
(*ar go* in breton means: the yeast)
### Context
- Castopod: v1.0.0-beta.19
- OS: Debian
- Browser: Firefox
- Web server: Nginx (behind Traefik reverse-proxy and through Docker)
### Possible fixes
- allow for 1 or 2-letter keyword searches
- explicitly disallow it
issue