Update size limits for SCA artifacts

What does this MR do?

This is an implementation of https://gitlab.com/gitlab-org/gitlab/-/issues/220398

Setting size limits for dependency_scanning, container_scanning, license_scanning artifacts

Migration

rails db:migrate

== 20200727142337 UpdateDefaultsForScaArtifacts: migrating ====================
-- change_column_default(:plan_limits, :ci_max_artifact_size_dependency_scanning, 350)
   -> 0.0088s
-- change_column_default(:plan_limits, :ci_max_artifact_size_container_scanning, 150)
   -> 0.0036s
-- change_column_default(:plan_limits, :ci_max_artifact_size_license_scanning, 100)
   -> 0.0030s
== 20200727142337 UpdateDefaultsForScaArtifacts: migrated (0.0155s) ===========

rails db:rollback

== 20200727142337 UpdateDefaultsForScaArtifacts: reverting ====================
-- change_column_default(:plan_limits, :ci_max_artifact_size_dependency_scanning, 0)
   -> 0.0058s
-- change_column_default(:plan_limits, :ci_max_artifact_size_container_scanning, 0)
   -> 0.0035s
-- change_column_default(:plan_limits, :ci_max_artifact_size_license_scanning, 0)
   -> 0.0038s
== 20200727142337 UpdateDefaultsForScaArtifacts: reverted (0.0133s) ===========

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done