Remove empty state

[chimon2000]

This pr includes several 1.0 changes.

• Removing empty states
• Adding state predicates
• Enhancing errors with dynamic errors and stack traces.

Work left (if wip):

n/a

Related Issue

Resolves #7, #10, #9

How Has This Been Tested?

Automated tests

Types of changes

• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

[codecov]

Codecov Report

Merging #11 into master will increase coverage by 3.18%.
The diff coverage is 84.25%.

@@            Coverage Diff             @@
##           master      #11      +/-   ##
==========================================
+ Coverage   76.56%   79.75%   +3.18%     
==========================================
  Files           1        2       +1     
  Lines         192      242      +50     
==========================================
+ Hits          147      193      +46     
- Misses         45       49       +4     

Impacted Files	Coverage Δ
packages/remote_state/lib/remote_state.dart	0.00% <0.00%> (ø)
...ackages/remote_state/lib/remote_state.freezed.dart	82.47% <91.00%> (+5.91%)	⬆️

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