TPAC: Standardize i18n file installation

TPAC: Standardize i18n file installation

Make TPAC i18n files act like any other i18n file. In short:

1. When in build/i18n, a 'make LOCALE=fr-CA install' will copy
   the i18n file into the Open-ILS/src/data/locale directory.
2. In the build root, a 'make install' will copy all files from
   Open-ILS/src/data/locale into (by default) the
   /openils/var/data/locale directory.

This also means that when tarballs are created, all of the locales will
get packaged appropriately.

This commit also updates eg_vhost.conf to provide working out-of-the-box
examples for any installed locales, by using the names of the actual
PO files, and adds some contextual comments to explain how the
configuration directives work.

Signed-off-by: Dan Scott <dscott@laurentian.ca>