[INJICERT-434] compute svg template multibase&sha256 per spec

[vharsh]

How to use this feature ?

• If mosip.certify.issuer.svg.template.id feature is set to a valid credential-id in the DB, it's renderMethod's hash digest will be available for templating with the key _renderMethodSVGdigest.
• This action will only be performed for the VC download requests which download VC 2.0 templates, i.e. have
• The template authors should use the _renderMethodSVGdigest placeholder in the template to dynamically fill in the SVG template's optional hash digest as per this spec
• For longer term use, it's recommended that authors hardcode this value in the VC 2.0 template

Config Changes required

• for a short term (say) when the template for a particular VC is undergoing rapid design changes the System Integrator can choose to set this mosip.certify.issuer.svg.template.id to a valid UUID present in the svg_template table and later hardcode the hashDigest value in the VC template itself to avoid re-evaluation of the hash on each VC download

Template changes required

• VC 2.0 template authors can optionally include the VC2.0 renderMethod key with valid values if they want to add support for VC rendering, by default this feature is turned off.

ref: https://w3c-ccg.github.io/vc-render-method/#svgrenderingtemplate

[jainhitesh9998]

can we add test cases here?