main/itstool: fix insufficiently quoted regular expressions for Python 3.12

testing/ardour: rebuild against boost 1.84

problem with regular expressions in itstool -r1:

$ itstool --version
/usr/bin/itstool:223: SyntaxWarning: invalid escape sequence '\s'
  if re.sub('\s+', ' ', text).strip() != '':
/usr/bin/itstool:321: SyntaxWarning: invalid escape sequence '\s'
  message = re.sub('\s+', ' ', message).strip()
/usr/bin/itstool:459: SyntaxWarning: invalid escape sequence '\s'
  return re.sub('\s+', ' ', self.locnote).strip()
/usr/bin/itstool:461: SyntaxWarning: invalid escape sequence '\s'
  return '(itstool) link: ' + re.sub('\s+', ' ', self.locnoteref).strip()
/usr/bin/itstool:892: SyntaxWarning: invalid escape sequence '\<'
  regex = re.compile('(.*) \<(.*)\>, (.*)')
/usr/bin/itstool:927: SyntaxWarning: invalid escape sequence '\s'
  if re.sub('\s+', '', prevtext) == '':
/usr/bin/itstool:1471: SyntaxWarning: invalid escape sequence '\.'
  _locale_pattern = re.compile('([a-zA-Z0-9-]+)(_[A-Za-z0-9]+)?(@[A-Za-z0-9]+)?(\.[A-Za-z0-9]+)?')
itstool 2.0.7