Add Dapr runtime version and enabled features to Metadata API

[shubham1172]

Description

Co-authored-by: @ItalyPaleAle

Add a runtime version to metadata root. It is kept in extended metadata for back-compat but should be deprecated later.
This also adds an 'enabledFeatures' key with list of preview features enabled.

daprd --app-id test --app-port 3001 --app-protocol grpc --dapr-http-port 3501 -- sleep 1000
curl localhost:3501/v1.0/metadata | jq .

{
  "id": "test",
  "runtimeVersion": "edge",
  "enabledFeatures": [
    "ServiceInvocationStreaming"
  ],
  "extended": {
    "daprRuntimeVersion": "edge"
  },
  "appConnectionProperties": {
    "port": 3001,
    "protocol": "grpc",
    "channelAddress": "127.0.0.1"
  },
}

Issue reference

Please reference the issue this PR will close: #6528

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Unit tests passing
• End-to-end tests passing
• Extended the documentation / Created issue in the https://github.com/dapr/docs/ repo: Add missing properties to the metadata API - Subscriptions, runtimeVersion, appConnectionProperties docs#3557
• Specification has been updated / Created issue in the https://github.com/dapr/docs/ repo: dapr/docs#[issue number]
• Provided sample for the feature / Created issue in the https://github.com/dapr/docs/ repo: dapr/docs#[issue number]

[codecov]

Codecov Report

Merging #6537 (a584a2b) into master (959eac3) will increase coverage by 0.05%.
The diff coverage is 87.50%.

@@            Coverage Diff             @@
##           master    #6537      +/-   ##
==========================================
+ Coverage   65.77%   65.83%   +0.05%     
==========================================
  Files         198      199       +1     
  Lines       19211    19224      +13     
==========================================
+ Hits        12636    12656      +20     
- Misses       5557     5559       +2     
+ Partials     1018     1009       -9     

Impacted Files	Coverage Δ
pkg/http/api.go	79.70% <0.00%> (-0.06%)	⬇️
pkg/grpc/api.go	74.35% <100.00%> (+0.03%)	⬆️
pkg/grpc/universalapi/api_metadata.go	95.52% <100.00%> (+0.13%)	⬆️
pkg/http/api_metadata.go	100.00% <100.00%> (ø)
pkg/runtime/runtime.go	64.79% <100.00%> (+0.13%)	⬆️

... and 5 files with indirect coverage changes

[daixiang0]

LGTM