GitLab

- add a README.chromium for the Speech Rule Engine
- move all files out of ...chromevox/[injected|background] to chromevoxclassic (which is the only user).
- add a gni file for liblouis library generation (for classic)

TBR=dmazzoni@chromium.org

Change-Id: I7e0c38a360438845edc39f0b34aeda502c0a4aab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1892553
Commit-Queue: David Tseng <dtseng@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711534}