Removes dashes option from Display tab so that it is only available
for series overrides. Also removes options for dash space and length
in series overrides and just uses the default values of 10 for both of
them.

Adding support for dashed lines using jquery.flot.dashes.js

docs: fixed redirects to panel docs for old location, caused by move in bd414c17

duplicate keys for auth.github for allow_sign_up

influxdb: fixed template variable interpolation of multi valued variables when using raw query editor mode, fixes #8165

Fixes #7914. Fixes #7921

feat: added api health endpoint that does not require auth and never creates sessions, returns db status as well. #3302

Fixes #7822

fix: better error handling / messsage when testing email notification when stmp is not configured, fixes #8093

* refactor util encryption library so it doesn't have to import log

* add util.SplitString to handle space and/or comma-separated config lines

* go fmt