Bump master version and codename to Electric Eel

Bump master version and codename to Electric Eel

This change adapts the distro versions and codename to match the next release 'Electric Eel'.
- Use 4.90.0 as version during inital development
- Adapt distro-codename

Change-Id: Ie2bd212cc8dd11a9bdbab2b9d53581406ff0a1e0
Signed-off-by: Jan-Simon Möller <jsmoeller@linuxfoundation.org>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/10449
Tested-by: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
ci-image-build: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>
ci-image-boot-test: Jenkins Job builder account <agl-jobbuilder@automotivelinux.org>