Generalize deploy maven-file builder

Generalize deploy maven-file builder

The builder hard codes the URL path which makes the builder
limit deploy capabilites only to external nexus repos and not
local file systems.

The change fixes the above issue by allowing the calling job
to define the repository path.
ex:

    "${NEXUS_URL}/content/repositories/$REPO_ID"
    "file://$WORKSPACE/m2repo"

Renamed variables:
'files-dir' to 'upload-files-dir'
'nexus-url-path' to 'maven-repo-url'
'$NEXUS_URL_PATH' to '$MAVEN_REPO_URL'

Change-Id: If0beb7f6dff76c18988c9a75b52c80358f16dff6
Signed-off-by: Anil Belur <abelur@linuxfoundation.org>