* [Android] Initial integration of Brave adaptive buttons
The Bookmarks button is the first in the list; the rest of the buttons will be added in separate PRs.
Important notes:
- override via `chromium_src` doesn't work for `patches/chrome-browser-ui-android-toolbar-adaptive_toolbar_enums.h.patch` since this file is parsed by `java_cpp_enum.py` to convert it to java enum
- patch to `java_cpp_enum.py` was added to be able to do 1 line patch, since upsteam parses each value as a separate line
- in `patches/chrome-browser-ui-android-toolbar-adaptive_toolbar_enums.h.patch` were added values for all planned Brave buttons to avoid additional patching for each consecutive PR
* Python patch optimisations
* Presubmit fixes
* Remove python patch in favour of multiline header patch