Add hard limits and pagination to everything

[tomlynchRNA]

• dont let somebody add an unlimited number of agents, tasks, etc
• add pagination to agent, task, tool, datasources, variables, etc
  • dont use a mongo .skip and .limit because this will cause skipped values if elements are added/removed while browsing, use $gt and $lt sorting based on the first or last element of a pages _id and use a .limit
• only pull most recent messages in a chat until scrolling up, same as session sidebar for scrolling down