Add configuration parameter to enable built-in hooks/filters

Add configuration parameter to enable built-in hooks/filters

If the configuration parameter filter.<filterDriverName>.useJGitBuiltin
is set to true then for all corresponding filters JGit will try to
execute the built-in filter instead of the filter-command which is
defined in git configuration. It will fallback to the non-built-in
filters if no built-in filters are registered or if constructing them
leads to exceptions. If set to false JGit will not try to execute
built-in filters for the specified filter driver.

Example: The configuration contains the following lines

  [filter "lfs"]
    clean = git-lfs clean -- %f
    smudge = git-lfs smudge -- %f
    useJGitBuiltin = true

Addtionally the .gitattributes file in the root of the working tree
contains:

    *.bin filter=lfs

In this case when new content is added similar to "git add 1.bin" then
the following will happen:

  - jgit will check whether a built-in command factory was registered
    for the command "jgit://builtin/lfs/clean". If that is true the
    factory is used to create a built-in filter command and that
    command is used to filter the content
  - Otherwise jgit will call the external program "git lfs clean ..."
    to do the filtering

Change-Id: Idadb1db06b1e89e7031d7ed6319904973c367d38