push: move phases synchronisation function in its own function Now that every necessary information is held in the `pushoperation` object, we can finally extract the phase synchronisation phase to it's own function. This is the first concrete block of code we extract from the huge push function. Hooray! This changeset is pure code movement only.

push: move outgoing object in the push object The set of outgoing and common changeset are used by phases to compute the new common set between local and remote. So we need to move it into the object to extract the phase sync from the god function. Note that this information will be used by obsolescence markers too.

push: move push return value in the push object The return code convey information about the success of changeset push. This is used by phases to compute the new common set between local and remote. So we need to move it into the object to extract the phase sync from the god function. Note that this information will be used by obsolescence markers too.

push: move local phase move in a normal function We now have the modularity for simpler approach `localphasemove`.

push: explicitly feed pushop to localphasemove Now that pushop is holding all the push related data, we do not really need a closure anymore. So we start feeding the object to `localphasemove` and will make it a normal function in the next commit.

push: move local lock logic in pushoperation During push, we try to lock the local repo to move local phase according to what we saw/pushed on the remote repo. Locking the repo may fail, in that case we let the push proceed without local phase movement (printing warning). This mean we have code in phase synchronisation that will check if the local repo is locked or not. we need to move this information in the push object to be able to extract the phase synchronisation in its own function. This is done as a boolean because putting reference to the actual lock outside of the main function sounded a bad idea.

push: move obsolescence related message into _pushobsolescence function No good reason to have them in the main fonction.

push: drop now outdated comment This `_pushobsolete` now exist for modularity purpose.

push: feed pushoperation object to _pushobsolete function This will allow the obsolete marker synchronisation to have full information on the ongoing push and pass information to other operation.

push: move obsolescence marker exchange in the exchange module The obsolescence marker exchange code was already extracted during a previous cycle. We are moving the extracted functio in this module. This function will read and write data in the `pushoperation` object and I prefer to have all core function collaborating through this object in the same place. This changeset is pure code movement only. Code change for direct consumption of the `pushoperation` object will come later.