port to Kotlin + drop NodeJS

[tomholub]

To make progress on #1044 and other issues, we need to port existing TypeScript functionality.

This is a master issue that tracks the various things to port.

• (Ivan) zxcvbnStrengthBar porting - port zxcvbnStrengthBar #1061
• (Ivan) MsgBlockParser for parsing pgp blocks - port MsgBlockParser from TypeScript to Kotlinpgp message block parser  #1052
• (Ivan) parsing of several keys at a time + parse encrypted keys parsing of several keys at a time in Kotlin + expect potentially encrypted keys #1053
• (Den) encrypt files - can use PGPainless directly port encryptFile to use PGPainless #1059
• (Den) encrypt + encode encrypted/plain emails (either inline or pgp/mime) encrypt + encode encrypted/plain emails #1058 inprogress
• (Den) generate keys - can use PGPainless directly - generate keys using PGPainless #1055
• (Ivan) decrypt keys - can use PGPainless directly encrypt and decrypt keys using pgpainless #1098
• (Ivan) encrypt keys - can use PGPainless directly encrypt and decrypt keys using pgpainless #1098
• (Den) gmailBackupSearch - maybe this is not used? node -> gmailBackupSearch used? should port it #1056
• (Den) parseDateStr - javascript has a "magic" date parser we use that we'll need in Kotlin. Maybe some mail library has this (we use it to parse email headers) - use JavaMail as a replacement for parseDateStr #1062
• (Ivan) decrypt files - can use PGPainless directly but need to match error scenarios to existing behavior implement pgp decrypt method that mimics error behavior #1060 inprogress
• (Ivan) parsing/decrypting of complex PGP messages parsing/decrypting of complex PGP messages in Kotlin #1057 but first need to do implement pgp decrypt method that mimics error behavior #1060
• (Den) switch to Kotlin decryption/parsing(decrypt large messages and pgp/mime encoded files of any size #1101)
• (Den) drop NodeJS

NodeJS functionality used within Android app is available here: https://github.com/FlowCrypt/flowcrypt-mobile-core/blob/master/source/mobile-interface/endpoints.ts