Bug 25387: Warn when merging different authority types

Bug 25387: Warn when merging different authority types

Merging two different authorities types can result in the loss of some
field. This patch adds a warning when merging different type of
authorities and add more display of authorities types during merge.

To test:
1- Find two authorities you what to merge. Be sure that these
authorities have different type
2- Search for these authorities (be sure to have both results on the
results page)
3- For the first authority click on "Actions" then on "Merge", same for
the second one
4- Check that koha is asking you to choose a framework and that
authority types are not displayed
5- Choose a framework, then click on next
6- Check that the authority type is not displayed in the tabs and that
no warning appear
7- Apply the patch
8- Repeat step 1 to 3 again
9- Check that authority type is now displayed next to their ID
10- Repeate setp 5 again
11- Check that the authority types is now displayed in the tabs next to
their ID and that a warning appear

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>