Adds Default TTL Option for Redis State Store

[berndverst]

Description

Redis unlike other databases that support TTL does not have an option to set a default TTL at the database or table / collection level.

This addition to the Redis State Store component allows defining a default TTL to be used whenever an individual State Store request does not specify a TTL.

Fixes #1060

• Code compiles correctly
• Created/updated tests
• Extended the documentation / Created issue in the https://github.com/dapr/docs/ repo: dapr/docs#[issue number]

[berndverst]

With this PR the component YAML will include a ttlInSeconds option (completely optional) to set a default TTL.

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
  name: <NAME>
  namespace: <NAMESPACE>
spec:
  type: state.redis
  version: v1
  metadata:
  - name: redisHost
    value: <HOST>
  - name: redisPassword
    value: <PASSWORD>
  - name: enableTLS
    value: <bool> # Optional. Allowed: true, false.
  - name: failover
    value: <bool> # Optional. Allowed: true, false.
  - name: sentinelMasterName
    value: <string> # Optional
  - name: maxRetries
    value: # Optional
  - name: maxRetryBackoff
    value: # Optional
  - name: ttlInSeconds
    value: <int> # Optional

[codecov]

Codecov Report

Merging #1059 (a773cdd) into master (253ef85) will decrease coverage by 0.00%.
The diff coverage is 33.33%.

@@            Coverage Diff             @@
##           master    #1059      +/-   ##
==========================================
- Coverage   34.53%   34.53%   -0.01%     
==========================================
  Files         132      132              
  Lines       10870    10882      +12     
==========================================
+ Hits         3754     3758       +4     
- Misses       6736     6744       +8     
  Partials      380      380              

Impacted Files	Coverage Δ
state/redis/redis.go	42.22% <33.33%> (-0.64%)	⬇️

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