stabilize_*()

[jonthegeek]

Export these stabilize_*() functions:

• stabilize_int64()
• stabilize_int()
• stabilize_date()
• stabilize_chr()
• stabilize_base64_to_chr()
• stabilize_double()
• stabilize_datetime()
• stabilize_structured_lgl()
• stabilize_duration()
• stabilize_time()
• stabilize_binary_to_raw()
• stabilize_base64url_to_chr()
• stabilize_uuid()

But consider where these should live, and whether this is the best approach. Deciding somewhat in beekeeper. This needs to be bidirectional in a lot of cases, so a class with to_*() methods (and thus stabilize_*() methods) might make the most sense.