serveronly: deduplicate code with the main evolve extension Now that 'serveonly' is a sub module of evolve. We can access its content in evolve. As a result we stop duplicating code all common parts are defined in the 'serveronly' module and imported by evolve when needed.

serveronly: clean up imports remove unused one and arrange them

compat: just use '_callcompressable' That API is available in all version we supports.

compat: drop bookmark compatibility layer All the version we now supports have the 'new' API.

compat: drop compat for older wireproto implementation We only support Mercurial version with these attributes.

compat: always use the strip revset from core We only support versions that defines it.

compat: drop support for ancestral pushop object Pushoperation object have a 'cgresult' attribute in all the versions we support.

compat: drop compatibility layer around update We now support only versions with the new API.

compat: drop compatibility layer for 'tryimportone' Return is now homogeneous for all the version we support.

compat: drop superfluous summary output All versions we support issues this output.