Bug 8068: Standardize terms used on acquisitions statistics

Bug 8068: Standardize terms used on acquisitions statistics

branch > library
budget > fund
bookseller, supplier > vendor
and capitalization

To test:
1) Go to Reports > Acquisitions statistics
2) Check the labels and options of the form for correctness.
3) Run a few test searches to make sure functionality is
   unchanged.

Unfortunately, some strings are from the .pl file, so a follow
up moving those to the templates is needed.
To make the changes consistent I have changed them in the .pl file.

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>