Offset template medical dates on date of birth

[bobintetley]

At present, when copying template animals the dates assigned to medical, vacc and tests are calculated as:

today + (template required date - template intake)

For puppies and kittens, this is not always the desired behaviour as vaccines and neuter/spay surgeries are done at a certain age.

The option should be available to use a date of birth offset rather than an intake date offset for some vacc, medical and tests. It should be triggered by the word DOB being present in the comments for those items. Where that's the case, the difference should be:

dob + (template required date - template date of birth)

[bobintetley]

This might be a lot simpler and the clue is in the description - use date of birth for any Baby template and use intake date for adults. This makes this fix a lot more trivial (and needs to be documented).

[bobintetley]

Talked to a heavy user of this feature - would break everything for them. As with the original issue, we need a method to indicate that DOB is to be used as an offset. Either on a per item basis (as originally suggested) or per animal/template basis.