localrepo: use _buildstatus from context

context: add _buildstatus method This method is a copy of localstatus.status's core logic. Later patches will clean up some of the dense coditionals in the for loop.

localrepo: remove workingctx logic already moved to context

localrepo: move the order of local variables This movement is a small step in getting rid of the 'if ... else' logic for testing the current working directory with its parent. Previously, the deleted, unknown, and ignored variables were set in a combination of before an 'if ... else' block and within the block. This moves the variables to be set outside the loop in one common place.

localrepo: factor out _manifestmatch logic for workingctx

localrepo: use _manifestmatches instead of duplicating logic

basectx: add _manifestmatches method This method is a duplicate of localrepo.mfmatches and sets the stage for factoring localrepo.status into a context method that will be customizable based on inheritance and object type.

localrepo: always set the variable r in status method This is a small patch to help streamline keeping tracking of the list of files for status in a variable already called 'r' ('s' is for subrepos in this method). We now move the setting of it out of an 'if' block so that we can later refactor more code into the context objects.