We need to add UI error to network discovery fields for the following scenarios of errors:

• open macro for item timeout
• configuration of snmp items
• exceeding the limit of dcheks (memory limit)
• exceeding the limit of file descriptors (in case of big number of concurrent checks) - if possible to do

Additional:

• rename the concurrent checks limiter to "Maximum concurrent checks per type" (not drule)
• add https as async check (last one is easy to add - other tcp_expect() based checks are  already done).