Update app connectors models and types

[0xGabi]

This PR includes two changes:

1. Rename connector entities -> models
2. Move data interfaces into types file.

The changes were done on the Voting, Tokens, and Finance app connectors.

[codecov]

Codecov Report

Merging #191 into master will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #191   +/-   ##
=======================================
  Coverage   32.68%   32.68%           
=======================================
  Files          96       96           
  Lines        1741     1741           
  Branches      273      273           
=======================================
  Hits          569      569           
  Misses       1172     1172           

Flag	Coverage Δ
#unittests	32.68% <100.00%> (ø)

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Impacted Files	Coverage Δ
packages/connect-finance/src/models/Finance.ts	5.55% <ø> (ø)
packages/connect-finance/src/models/Transaction.ts	100.00% <ø> (ø)
packages/connect-finance/src/thegraph/connector.ts	54.83% <ø> (ø)
packages/connect-tokens/src/models/Token.ts	100.00% <ø> (ø)
packages/connect-tokens/src/models/TokenHolder.ts	100.00% <ø> (ø)
packages/connect-tokens/src/models/Tokens.ts	86.66% <ø> (ø)
packages/connect-tokens/src/thegraph/connector.ts	76.47% <ø> (ø)
packages/connect-voting/src/models/Vote.ts	90.00% <ø> (ø)
packages/connect-voting/src/models/Voting.ts	7.69% <ø> (ø)
packages/connect-voting/src/thegraph/connector.ts	54.83% <ø> (ø)
... and 14 more

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