MINOR: converter: adding support for url_enc

add base support for url encode following RFC3986, supporting `query`
type only.

- add test checking url_enc/url_dec/url_enc
- update documentation
- leave the door open for future changes

this should resolve github issue #941

Signed-off-by: William Dauchy <wdauchy@gmail.com>
(cherry picked from commit 888b0ae8cf92cb23112bd8920b256b0bdf67caf0)
[wt: updated regtest to mention 2.3]
Signed-off-by: Willy Tarreau <w@1wt.eu>
3 files changed