ui: add support for casting columns to the table viewer

[altimin]

Allow the user to change the type of the column explicitly by
casting the column to one of the types in PerfettoSQL.

Each column can be cast to any primitive PerfettoSQL type (int, double, string, boolean, timestamp, duration) and
select id types (slice id, utid, upid). If a column already has a given type, it can't be cast to it again. If the column
is already as cast column, a further cast would apply to the original column (so cast(cast(foo)) simplifies to
cast(foo)).

Known limitations

• Only a small number of id types are supported for now (slice id, utid, upid).
• Cast relies on sqlite cast, which is too permissive for casts from string to int / double.