alerting: adds tests for the median reducer

add minimal permission to docs

adds a test that verify that null values are not used
when calculating the median value in alerting

closes #10056

Gitlab -> GitLab

typo fix for "has"

alerting: increase default duration for queries

Add [hash] to grafana.{light,dark}.css

we should promote using longer queries since this should
increase the quality of the alerts. only using a 5min range
means that we will only have 4 datapoints in data is written
every min which is not good enough for the generic alert rule

Fix minor JSON typo in HTTP API docs

Updated login page logo & wordmark and responsive behavior

[skip ci]

Add delta window function to postgres query builder

Explore: async starts of language provider

Org page to react

Increase Telegram captions length limit

Unlike the increase function delta doesn't check for resets
and can go negative. This is similar to the prometheus delta
function.