add Ulid.Cli project.

[itn3000]

this PR adds the ULID utility tool project. current implementation is only new command.

remaining works are

• [X] package name
  • currently, Ulid.Cli
• [X] command name
  • currently, dotnet-ulid
• [X] commands
  • currently, only dotnet-ulid generate command
• [X] package metadata
  • almost element can be copied from Ulid

current command interface(from dotnet ulid help)

generate: create ULID
-b, -base64: [default=False]output as base64 format, or output base32 if false
-t, -timestamp: [default=null]timestamp(converted to UTC, ISO8601 format recommended)
-r, -randomness: [default=null]randomness bytes(formatted as Base32, must be 16 characters, case insensitive)

[neuecc]

thanks, good project! As a use case that I consider, when getting the range(to query sql) maybe requires to generate start-datetime(randomness is 0), end-datetime(randomness is max).

[itn3000]

fixes are almost done, please review it

[neuecc]

thanks, I'll check soon(today)

[neuecc]

Thank you, I'm happy to your great contribution!