Update POTFILES and translation template

[ryonakano]

Description

The translation template is outdated and missing some strings, which means translators can't complete their work. So, I updated the POTFILES and translation template.

I would like the maintainers of Bottles to enable the Update PO files to match POT (msgmerge) addon on Hosted Weblate, because updating .po files too in this PR would cause conflicts in #3313. Enabling this addon makes Weblate update .po from .pot automatically.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• Run git grep -l -w _\( -- bottles > po/POTFILES
• Manually edit POTFILES because the previous command removes comments and paths under data/ dir
• Run meson setup builddir --prefix=/usr -Ddevel=true
• Run ninja -C builddir
• Run ninja -C builddir bottles-pot

[fab-sonarqube]

SonarQube Quality Gate

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

[github-actions]

Pylint result on modfied files:

[kbdharun]

LGTM, Thanks for your contribution.

I will send a reminder to Mirkob about the add-on (we have been discussing about it for a while).

[ryonakano]

Converting to draft since I'd like to re-update the pot after #3333 get merged.