Add ICSP package in to the main branch to pkg/iscp

[kononovn]

Package location: /pkg/icsp.go

ImageContentSourcePolicy package should support the following public api:

Builder: struct

• [x] NewBuilder - Creates role object with single mirror. Basic struct
• [x] WithRepositoryDigestMirror - Appends additional mirrors to basic struct.
• [x] Create - Creates ImageContentSourcePolicy Rule on a cluster.
• [x] Delete - Deletes ImageContentSourcePolicy Rule on from cluster.
• [x] Update - Updates ImageContentSourcePolicy Rule on a cluster.
• [x] Exists - Check if particular rule exist in cluster.

[vkolodny]

@kononovn please assign me to this task - I cannot autoassign

[vkolodny]

@trewest @kononovn Do we need all ***AndWait functions here ?