make text area focused by default

When multiple Terminal tabs are open, activating Terminal tool window for the first time after IDE startup shouldn't start all shell processes corresponding to the opened tabs. That would allow save some CPU, avoid concurrent shell logins and initialize a visible tab a bit faster. Solution: a shell process should be started lazily, when its tab is shown.

It is difficult to synchronize user registry life cycle with that of the index. There are some cases when user registry could be rebuilt while index is not. So when log is loaded users that are loaded into the registry acquire ids different from the indexed ones. The solution is to use separate components for the separate functions: user registry for storing users for completion (as was done before) and another enumerator inside the index specifically for indexing purposes.

IDEA-198803, IDEA-201422

ssh can call SSH_ASKPASS handler, passing multiline comment to it (separated by '\n').
`cmd /c script.bat args` command cannot handle such arguments and passes only the first line down to the script.

git-for-windows actually supports shell scripts as SSH_ASKPASS/GIT_ASKPASS, that can be used as workaround.

Another solution could be to use '.exe' binary executable, that gets JVM options from ENV to communicate via XML RPC.

The action is not experimental anymore and therefore does not need to be hidden.

Restore original state after test is complete
Without this change git for win cannot work with GH:E installation due to inaccessible SSL cert

CaretModelImpl.beforeDocumentChange->CaretImpl.updateCachedStateIfNeeded->CaretImpl.getOffset call chain cannot work with myIsInUpdate = true,
previously (by accident) we never got into such a call chain (due to code in EditorImpl.beforeChangedUpdate)

* added `cidr.test.framework.showIndexingAsTask:false` registry value that hide any test indexing activity
* small logging improvement

update ui after discussions with UX