Copy changes in PMGTools from 21.2 into master and make it compile

Copy changes in PMGTools from branch 21.2 and fix minor things to make it compile without warnings and errors

• changed old 'Root::TAccept' to new 'asg::AcceptInfo'
• removed obsolete factory entries for components in PMGTools
• adjusted variable names to compile with naming convention
• added checks of returned StatusCode
• removed one keyword mutable where not necessary