Upstream is set to deprecated, and delete all occurrences of
`base::StringPiece`, and replace it with `std::string_view`, and
according correspondent types.
This change removes the use of `base::StringPiece`, and of the headers
as well across the Brave codebase.
HTTPS by default on Desktop
- Disabled, Standard, Strict modes
- Controlled by global and per-site shields settings
- Merge UI with HTTPS-Only Mode
- Behind HttpsByDefault feature flag
- Browser tests for each setting