Feat: TemplateService to replace tokens in a string

[iJungleboy]

I'm submitting a

[x] feature request

...about

[x] Razor templating

Current Behavior / Expected Behavior

There are various cases where a string should be able to contain placeholders, which would then be replaced by things such as the date-time or values from an entity.

Internally 2sxc has this functionality, but it's not available on the public API, so we want to make this possible.

Steps ca.

• Create a service, probably an ITemplateService
• Create a Parse("string") mechanism or something
• Create various features to add/override certain sources with custom sources, eg. from an Entity

Your environment

• 2sxc version(s): 17.07