fix(core): read paths.config instead of env variable

[spkjp]

Summary

Fixes the config lookup. Additionally, packages/core/bin/config/{network}/app.js needs to be manually copied to ~/.config/ark-core/{network} or ark config:reset.

Resolves:

10|ark-forger  | [2019-10-26 11:44:26.760] ERROR: InvalidTransactionBytesError: Failed to deserialize transaction, encountered invalid bytes: Unknown transaction type: 2/2
10|ark-forger  |     at Function.fromBytesUnsafe (/home/ark/core/packages/crypto/dist/transactions/factory.js:34:19)
10|ark-forger  |     at response.transactions.map (/home/ark/core/packages/core-forger/dist/manager.js:147:106)
10|ark-forger  |     at Array.map (<anonymous>)
10|ark-forger  |     at ForgerManager.getTransactionsForForging 

Checklist

• Documentation (if necessary)
• Tests (if necessary)
• Ready to be merged

[codecov]

Codecov Report

Merging #3142 into develop will decrease coverage by <.01%.
The diff coverage is 0%.

@@             Coverage Diff             @@
##           develop    #3142      +/-   ##
===========================================
- Coverage    29.64%   29.64%   -0.01%     
===========================================
  Files          425      425              
  Lines        11886    11887       +1     
  Branches      1630     1630              
===========================================
  Hits          3524     3524              
- Misses        8330     8332       +2     
+ Partials        32       31       -1

Impacted Files	Coverage Δ
packages/core/src/commands/snapshot/dump.ts	0% <0%> (ø)	⬆️
packages/core/src/commands/core/run.ts	0% <0%> (ø)	⬆️
packages/core/src/commands/snapshot/verify.ts	0% <0%> (ø)	⬆️
packages/core/src/commands/relay/run.ts	0% <0%> (ø)	⬆️
packages/core/src/utils.ts	0% <0%> (ø)	⬆️
packages/core/src/commands/forger/run.ts	0% <0%> (ø)	⬆️
packages/core/src/helpers/replay.ts	0% <0%> (ø)	⬆️
packages/core/src/commands/snapshot/rollback.ts	0% <0%> (ø)	⬆️
packages/core/src/commands/chain/replay.ts	0% <0%> (ø)	⬆️
packages/core/src/helpers/snapshot.ts	0% <0%> (ø)	⬆️
... and 2 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 2375d68...f56400a. Read the comment docs.