This PR brings support for `history` list to
list in the following agreed format
```
~ mc admin config history list -n 2 myminio
RestoreId: df0ebb1e-69b0-4043-b9dd-ab54508f2897
Date: Mon, 04 Nov 2019 17:27:27 GMT
region name="us-east-1" state="on"
region name="us-east-1" state="on"
region name="us-east-1" state="on"
region name="us-east-1" state="on"
RestoreId: ecc6873a-0ed3-41f9-b03e-a2a1bab48b5f
Date: Mon, 04 Nov 2019 17:28:23 GMT
region name=us-east-1 state=off
```
This PR also moves the help templating and coloring to
fully `mc` side instead than `madmin` API.
- This PR allows config KVS to be validated properly
without being affected by ENV overrides, rejects
invalid values during set operation
- Expands unit tests and refactors the error handling
for notification targets, returns error instead of
ignoring targets for invalid KVS
- Does all the prep-work for implementing safe-mode
style operation for MinIO server, introduces a new
global variable to toggle safe mode based operations
NOTE: this PR itself doesn't provide safe mode operations
- adding oauth support to MinIO browser (#8400) by @kanagaraj
- supports multi-line get/set/del for all config fields
- add support for comments, allow toggle
- add extensive validation of config before saving
- support MinIO browser to support proper claims, using STS tokens
- env support for all config parameters, legacy envs are also
supported with all documentation now pointing to latest ENVs
- preserve accessKey/secretKey from FS mode setups
- add history support implements three APIs
- ClearHistory
- RestoreHistory
- ListHistory
- add help command support for each config parameters
- all the bug fixes after migration to KV, and other bug
fixes encountered during testing.
