Replace inheritance from ASFormatter with composition

AStyleFormatter resorted to hiding member functions of its base class to
reduce the likelihood of calling them unintentionally. Still it used to
call some of the base class functions by mistake until recently. Making
ASFormatter a data member instead of inheriting from it greatly reduces
the risk of such mistakes in the future.
1 job for !121 with fix-astyle-plugin-options in 64 minutes and 56 seconds (queued for 4 minutes and 7 seconds)
latest detached
Status Job ID Name Coverage
  Build
failed #40249
linux kf5-qt5 qt5.12

01:04:56

 
Name Stage Failure
failed
linux kf5-qt5 qt5.12 Build The script exceeded the maximum execution time set for the job
        Start  86: test_qmljsdeclarations
kf5.kinit.klauncher: new app ":1.49"
kf5.kinit.klauncher: new app "org.kdevelop.kdevplatform-lock-0c89e835-c35a-4373-b2cd-8af1765eb014"
86/124 Test #86: test_qmljsdeclarations .................. Passed 4.30 sec
Start 87: test_files
kf5.kinit.klauncher: new app ":1.50"
kf5.kinit.klauncher: new app "org.kdevelop.kdevplatform-lock-7a67a6a1-a04d-458a-b55e-03a05bdb1762"
Pulling docker image gitlab/gitlab-runner-helper:x86_64-1b659122 ...
ERROR: Job failed: execution took longer than 1h0m0s seconds