Every role permission will be represented by 12 bits to handle

• no permission
• permission with no prefixes
• permission with each propagation prefix
• permission with each filtering prefix
• permission with each combination of propagation/filtering prefixes.

This diff just handles computing those 12-bits for a single string-encoded role permission. We do this by creating a lookup table where each possible permission variant is represented by a bit, we then use ParsesdThreadPermissionString to lookup bit representation for permission of certain variant.

Unit tests to test this function in place. Function will be used by rolePermissionsToBitmaskHex to encode bitmask for all permissions... which will have thorough unit tests of its own.