Update migrator to read the node snapshot

[nagdahimanshu]

What was the problem?

This PR resolves #131

How was it solved?

• Remove support for min-compatible-version, snapshot-path and use-existing-snapshot, if min-compatible-version is forced to 3.0.5 in the application
• Lisk Migrator validates from the node:info (Lisk Core v3) if the backup.height matches the user specified snapshot_height
• Once the snapshot-height is finalized, the migrator now reads the backup (~/.lisk/lisk-core/data/backup by default or /data/backup) to start the migration process
• Update lisk-db version and refactor code
• Fix unit tests
• Update docs

How was it tested?

Local against testnet

[codecov]

Codecov Report

Merging #133 (840d9b7) into release/2.0.0 (dda7e2b) will increase coverage by 0.15%.
The diff coverage is 100.00%.

Additional details and impacted files

@@                Coverage Diff                @@
##           release/2.0.0     #133      +/-   ##
=================================================
+ Coverage          93.34%   93.49%   +0.15%     
=================================================
  Files                 20       20              
  Lines                556      569      +13     
  Branches              70       74       +4     
=================================================
+ Hits                 519      532      +13     
  Misses                37       37              

Files Changed	Coverage Δ
src/assets/pos.ts	92.85% <100.00%> (+1.07%)	⬆️
src/constants.ts	100.00% <100.00%> (ø)
src/createAsset.ts	97.18% <100.00%> (ø)
src/utils/transaction.ts	100.00% <100.00%> (ø)