[candidate_list] Translate site

[driusan]

This adds translations for "site" on the candidate_list page (both dropdown and data table) as an example of how to handle database translations.

The text domain of the table name (in the case of sites, the "psc" table) has the options that are translated. This can be placed in the project/locale/$lang/LC_MESSAGES/psc.po file and compiled with msgfmt -o psc.mo psc.po.

I tested this using the following .po for raisinbread's sites and Japanese (translations from Google Translate)

msgid ""
msgstr ""
"Project-Id-Version: LORIS 28\n"
"Report-Msgid-Bugs-To: https://github.com/aces/Loris/issues\n"
"POT-Creation-Date: 2025-04-08 14:37-0400\n"
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
"Language-Team: LANGUAGE <LL@li.org>\n"
"Language: ja\n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=UTF-8\n"
"Content-Transfer-Encoding: 8bit\n"

msgid "Data Coordinating Center"
msgstr "データ調整センター"

msgid "Montreal"
msgstr "モントリオール"

msgid "Ottawa"
msgstr "オタワ"

msgid "Rome"
msgstr "ローマ"

This is not included in the PR, because the site names are LORIS install specific. I intend to send a different PR with a script to extract a .pot file from the database values for a table.