Add support for JuiceSSH generated ed25519 keys

[TranceLove]

Reported from TeamAmaze/AmazeFileManager#2976, it was found the key uses aes-128-cbc which is currently not supported by sshj. This change adds support for it.

To enable support for this, also eliminated hardcoding byte array size for key and IV, as a result of BCrypt.pbkdf().

[codecov-commenter]

Codecov Report

Merging #770 (cc9c68b) into master (9a939d0) will increase coverage by 0.07%.
The diff coverage is 80.00%.

❗ Current head cc9c68b differs from pull request most recent head a90ef6e. Consider uploading reports for the commit a90ef6e to get more accurate results

@@             Coverage Diff              @@
##             master     #770      +/-   ##
============================================
+ Coverage     64.39%   64.47%   +0.07%     
- Complexity     1459     1461       +2     
============================================
  Files           211      211              
  Lines          8615     8617       +2     
  Branches        806      807       +1     
============================================
+ Hits           5548     5556       +8     
+ Misses         2643     2639       -4     
+ Partials        424      422       -2     

Impacted Files	Coverage Δ
...sshj/userauth/keyprovider/OpenSSHKeyV1KeyFile.java	83.10% <80.00%> (+0.23%)	⬆️
...t/schmizz/sshj/connection/ConnectionException.java	33.33% <0.00%> (-11.12%)	⬇️
...zz/sshj/connection/channel/ChannelInputStream.java	86.15% <0.00%> (-3.08%)	⬇️
.../main/java/net/schmizz/sshj/sftp/PacketReader.java	95.74% <0.00%> (+4.25%)	⬆️
...ain/java/net/schmizz/sshj/common/SSHException.java	74.19% <0.00%> (+12.90%)	⬆️
...net/schmizz/sshj/transport/TransportException.java	55.55% <0.00%> (+22.22%)	⬆️

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[hierynomus]

Thanks, changes look good. Consider it merged!