[HatoholAddActionDialog] Hide "Trigger" filter for incident setting

Because the "Trigger" filter works with "Host", and the "Host"
filter is already hidden for incident setting.
[IncidentSettingsView] Remove "Trigger" column
[IncidentTrackersEditor] Add placeholder attribute for the tracker ID entry
[HatoholAddActionDialog] Revise default value of selectTriggerSeverityCompType

Use "CMP_EQ_GT" dy default for incident settings.
[HatoholAddActionDialog] Hide trigger status filter for incident setting

Always use "TRIGGER_STATUS_PROBLEM" for incident setting to
simplify the UI and future expansion.
Merge pull request #605 from project-hatohol/simplify-incident-setting-ui

Simplify incident settings UI