eina: Adding API for base64 url encoding.
I have put the common encoding code in the common function. The 2 API's
call them with a flag. Thinking of doing the same way to decode
Signed-off-by: Srivardhan Hebbar <firstname.lastname@example.org>
Reviewers: cedric, jpeg
Differential Revision: https://phab.enlightenment.org/D3414