en_US language pack is not used in JIRA and is not up to date in TAC. We should remove it.

Unfortunately due to the TAC architecture we cannot simply remove en_US locale as it is used to generate language packs for other products.
There are two options:

• Talk to other products owners/experts and ask if they use en_US. If not then we can probably remove en_US locale from TAC.
• If en_US is used for other products we could change TAC somehow so it does not generate language packs for all products and all locales.