feat: config grouped by area, with per-provider timeouts and an update interval (#60)

Regroups the config, while there are no users to migrate:

- `ui`: icons, sourcesView, collapseGroups, loadDelay, expiryWarningDays
- `values`: revealTimeout, hideOnBlur, clipboardClear
- `storage`: cache, history
- `updates`: autoCheck (was updateCheck), autoCheckInterval (new, 24h by default), updateSources (was releases)
- `providers.timeout` (was timeout), plus `timeout` on azure, databricks and repos overriding it for that provider; `--timeout` still sets them all
- `sharing` (was share), in the config and in a repo's `.lazysecrets.yaml`

docs/config.md and the pages naming these keys are updated.

Reviewed-on: #60
Co-authored-by: Karl-Einar Bergstrøm <karl-einarb@outlook.com>

README.md

@@ -99,10 +99,10 @@ use most:
 
 lazysecrets never stores, caches or sends your secret values. It keeps the
 names and metadata of what you've loaded in a cache file readable only by
-you, to show it at once next time (`cache: false` turns it off). It talks
+you, to show it at once next time (`storage.cache: false` turns it off). It talks
 only to the services you use it with, and collects no usage data. The one
 call of its own is a daily check for a new release, on GitHub or else
-git.kebcloud.no, which `updateCheck: false` turns off.
+git.kebcloud.no, which `updates.autoCheck: false` turns off.
 
 ## Repositories