feat(dh): add TOOL_set_default_terminal function to set default terminal emulator
refactor(dh): rename TOOL_distrohopper_translate to TOOL_dh_translate
refactor(dh): replace hardcoded strings with variables in the dh script
refactor(lang): improve language translations and remove unnecessary escape characters
chore(lang): update language files formatting and translations
fix(dh): comment out unused export statements
fix(dh): fix typo in message string
fix(dh): fix typo in language directory name
fix(dh): fix typo in copying translation to system directory
refactor(dh): remove unused function WIP2
refactor(dh): rename function WIP to distrohopper_gui
refactor(dh): rename variable lang to LANGUAGE
refactor(dh): rename variable DH_CONFIG_DIR to DH_CONFIG_DIR_PATH
refactor(dh): rename variable DH_ICON_DIR to DH_ICON_DIR_PATH
refactor(dh): rename variable VMS_DIR to VM_DIR_PATH
refactor(dh): rename variable TERMINAL to DEFAULT_TERMINAL
refactor(dh): rename variable replace to REPLACE_CHAR
refactor(dh): rename variable portable_prefix to PORTABLE_PREFIX
refactor(dh): rename variable TMP_DIR to TEMP_DIR_PATH