release notes sidebar: display TOC nested levels

Signed-off-by: Lucas Dutra Nunes <ldnunes@ossystems.com.br>
release notes index: remove redundant title

Signed-off-by: Lucas Dutra Nunes <ldnunes@ossystems.com.br>
release notes introduction: remove stylesheet padding

Signed-off-by: Lucas Dutra Nunes <ldnunes@ossystems.com.br>
Remove blank line

Signed-off-by: Lucas Dutra Nunes <ldnunes@ossystems.com.br>
release notes: hovering over paragraph links makes it stand out more

Signed-off-by: Lucas Dutra Nunes <ldnunes@ossystems.com.br>
release notes: removed that ugly orange color from links

Now it is a nice blue color, while visited links are dark gray. Also
all links don't have decoration until hovering the cursor over, which
causes it to become underlined.

Signed-off-by: Lucas Dutra Nunes <ldnunes@ossystems.com.br>
release notes: tables are always centered

Signed-off-by: Lucas Dutra Nunes <ldnunes@ossystems.com.br>
release notes: search text input resized to look better

Signed-off-by: Lucas Dutra Nunes <ldnunes@ossystems.com.br>