Vault tool read value patch

This patch adds an option to the vault tool which allows you to read a value from the vault and have it printed to screen.

Please enter a Digit::  0: Store a secured attribute  1: Check whether a secured attribute exists  2: Remove secured attribute  3: Exit  4: Show secured attribute value
4
Task: Verify whether a secured attribute exists
Enter Vault Block:foo
Enter Attribute Name:bar
The value is [secret]

Steps to apply the patch

1. Download the source of Wildfly 15.0.1 and extract it.
2. Download wildfly_15.0.1_vault_read.patch and store it in the extracted directory.
3. Apply the patch by running patch -p1 <wildfly_15.0.1_vault_read.patch.
4. Build wildfly by running ./mvnw install.

You can then run the vault tool with ./build/target/wildfly-15.0.1.Final/bin/vault.sh

Note: It's best if you use JDK 8 for this. I wasn't able to compile wildfly with JDK 17