Feat/app env vars (#430)

* initial changes for env var support

* WIP

* Update applications.js

* JSON stringify before encrypting

* use call_hook.url

* env vars working

GET /v1/AppEnv?url=[URL] to trigger options request to URL and return app-schema
POST /v1/Applications with {env_vars: [OBJECT} to create app with env vars
PUT /v1/Applications/[SID] with {env_vars: [OBJECT} to change env vars
GET returns env vars

POST and PUT will also trigger an OPTIONS request to the call_hook url to get schema and then validate the env_vars against it

* update appenv cannot finish request.

* wip

* wip

* wip

* wip

---------

Co-authored-by: Dave Horton <daveh@beachdognet.com>
Co-authored-by: Quan HL <quan.luuhoang8@gmail.com>
Co-authored-by: Hoan Luu Huu <110280845+xquanluu@users.noreply.github.com>

lib/routes/api/speech-credentials.js

@@ -821,7 +821,6 @@ router.get('/:sid/test', async(req, res) => {
           SpeechCredential.ttsTestResult(sid, true);
         } catch (err) {
           let reason = err.message;
-          // if error is from bent, let get the body
           try {
             reason = await err.text();
           } catch {}
@@ -837,7 +836,6 @@ router.get('/:sid/test', async(req, res) => {
           SpeechCredential.ttsTestResult(sid, true);
         } catch (err) {
           let reason = err.message;
-          // if error is from bent, let get the body
           try {
             reason = await err.text();
           } catch {}