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>

internal/ui/app/usage.go

@@ -8,7 +8,7 @@ import (
 // Usage: revealing, copying, opening in the browser, sharing and jumping
 // to an item count as using it. The store keeps when each item was last
 // used and how often, for the Recent section of the jump list. The config's
-// history: false turns this off.
+// storage.history: false turns this off.
 
 // used counts a use of the remembered item key, keeping its context.
 func (m *Model) used(key string) {