widgets: add a re-useable filtered logread view

widgets: add a re-useable filtered logread view

Multiple apps introduced their own implementation of a syslog view,
filtered for just their own application logs.  Pull that out as a shared
view.  Some of these had _minor_ style differences, which has been
"standardized" now.  A full "widget" conversion would allow more end app
tuning of that, but is not implemented.

Signed-off-by: Karl Palsson <karlp@etactica.com>
app-nextdns: fix Logs title

Minor typo, introduced in 625abbf (convert simple controllers to
menu.json)

Signed-off-by: Karl Palsson <karlp@etactica.com>
luci-base: implement shared log reader view

Closes #5452

Signed-off-by: Paul Donald <newtwen@gmail.com>
(cherry picked from commit c5a65a839713ab7ac70e6a6b5a7331593f67a9a0)