Permissions and Roles

[bitfl0wer]

One should be able to modify, create and delete Roles and their permissions. This extends to modifying role and user permissions on channels and channel categories.

[bitfl0wer]

For Permissions: Right now, there exists an implementation of Spacebars bitwise permission flags, called src/types/entities/role.rs/PermissionFlags. I'd like to extend this in a way which makes it easy to
a) Calculate the actual permissions from a given String/u64 of permission flags
b) Do the reverse: Combine permissions to make a given String/u64 of permission flags.
Leaving this comment here as a sort of sticky note for myself.