Implement Gradle instance plugin

[pun-ky]

Features:

• tasks for creating self-extractable distributions: osgiDistribution
• tasks for controlling instances created under home directory: osgiUp, osgiHalt, osgiCreate, osgiDestroy, osgiReload

[pun-ky]

Nice to have will be fail safe combination of halt + destroy + create + up to start over with fresh env

[pun-ky]

Distribution task should include web manager and other default bundles like Felix DS / SCR, OSGi cmpn and Felix File install used by web-manager