Report Manager - Add new admin settings to better control schedule limits

[lbueno]

This idea aims to help on-premises installations or live connections to better control load.

The scenario: we have a big amount of users using the Report Manager plug-in, and we cannot limit the number of reports they can create or even the minimum periodicity for their schedules. Currently any user will be able to create a big number of reports, and those reports in a worst case scenario could be sent every hour. It could case a high usage of server resources. It is possible to setup the number of concurrent reports that will be processed, but depending on the number of reports it could cause bottlenecks and big deliver delays.

The idea: adding some new 'admin' settings to Report Manager plug-in:

- Maximum number of reports per user: defines the maximum number of reports a unique user can create. We could use 0 for unlimited (current behavior).

- Maximum number of reports per user group: defines the maximum number of reports a user group can create. Same ideia as the above, but related to user groups. It could be a unique setting for any user group, or maybe a map with specific limits for each user group.

- Minimum periodicity for scheduling: currently Report Manager offers the hours, days, week and months options. For instance, if this setting is set to days, then users will not be able to select hours when creating new schedules. Current existing schedules could be kept.