feat: allow token introspection as an authz option

[rsmayda]

Description of changes:

• Added IntrospectionOptions
• Defaults to use introspection if configuration is given
• Made jwksEndpoint optional
• made decodeJwtToken its own method
• Changed the AuthZ errors from logging as error to log as warn

Coverage results:

-----------------------------|---------|----------|---------|---------|-------------------
File                         | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
-----------------------------|---------|----------|---------|---------|-------------------
All files                    |   98.93 |    95.85 |     100 |   98.91 |
 loggerBuilder.ts            |     100 |      100 |     100 |     100 |
 smartAuthorizationHelper.ts |   97.22 |    94.23 |     100 |    97.2 | 186,210,220
 smartHandler.ts             |     100 |    96.04 |     100 |     100 | 204,280,285,303
 smartScopeHelper.ts         |     100 |     97.5 |     100 |     100 | 62
-----------------------------|---------|----------|---------|---------|-------------------

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[carvantes]

Overall looks good. Just a couple comments that may make the new config clearer