Revamp PII true/maybe/false

[Dav1dde]

See also: #5156

Instead of defining pii is true, maybe or false, we want to be able to determine which rules are applied on a field by field basis.

Now we can still keep true, maybe, false as shortcuts, but the idea is to make it possible to specify rules instead.

For example:

#[metastructure(pii = [])]
pub pii_false: Annotated<String>,
#[metastructure(pii = ["@user-defined"])]
pub pii_maybe: Annotated<String>,
#[metastructure(pii = ["@common"])]
pub pii_true: Annotated<String>,
#[metastructure(pii = ["@email:replace", "@creditcard:replace", "@user-defined"])]
pub new_and_powerful: Annotated<String>,

It should be possible to refer to rules directly from the annotation. @user-defined is nothing more than a PII rule group, where all user defined ("advanced") rules are put into.

[linear]

RELAY-160 Revamp PII true/maybe/false