MI - SECURITY section (Password Encryption doc) about docs-ei HOT 3 CLOSED

Completed the doc on encrypting passwords in configuration files[1] with new toml configs. The old content [4]

Other updates:

• The reference content on secure vault [1] was translated to a new doc called 'Customizing Secure Vault' [2]. This doc will be corrected through issue: #324
• A new toml configuration related to encryption was found. New page added with basic content [3]. This will be updated through issue: #322

Preview on netlify[5]

[1] https://github.com/wso2/docs-ei/blob/master/en/micro-integrator/docs/setup/security/encrypting_plain_text.md
[2] https://github.com/wso2/docs-ei/blob/master/en/micro-integrator/docs/references/security/customizing-secure-vault.md
[3] https://github.com/wso2/docs-ei/blob/master/en/micro-integrator/docs/setup/security/replace_passwords_env_variables_sys_properties.md
[4] https://docs.wso2.com/display/ADMIN44x/Encrypting+Passwords+with+Cipher+Tool

[5] https://wso2docs-configurationcatalog-3.netlify.com/setup/security/encrypting_plain_text/

from docs-ei.

@madushadhanushka - Could you please review?
Thanks!

from docs-ei.

Done.
https://ei.docs.wso2.com/en/latest/micro-integrator/setup/security/encrypting_plain_text/

from docs-ei.