[developermode] Implement installing from local package. Contributes to JB#47559

This allows enabling developer mode from local package and thus doesn't
require Internet or repository access. The package must not have
non-preinstalled requirements. Before installing version in package file
name is checked against -preload subpackage.

[developermode] Add repositoryAccessRequired property. Contributes to JB#47056

Repository access may be required if the local package does not exist or
it can not be installed for some reason. In that case developer mode
settings page must ask for repository access (usually some kind of
account).