[NXCM-4485] Add optional framework property for setting temp directory to be used when creating p2 agents

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NXCM-4485] Set temp directory under "target/p2/tmp

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Create provisioning agent only in one place

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Make possible to specify a location while creating agent

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NXCM-4660][NEXUS-5225] Delete agent directories after usage

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Merge pull request #5 from sonatype/nxcm-4485-use-nexus-temp-dir

REVIEW: P2 agent temp directory related fixes