Added "strict" to project.

[CarlosSolrac]

Instead of using process.env.VARIABLE, export uppercase variables.
process.env.VARIABLE is interpreted as "string | undefined" causing compiler errors.

.env.example

• change the SESSION_SECRET to pass "code spell checker"
• add NODE_ENV
• add SENDGRID
• add TZ to set timezone to UTC
• change MONGODB_URI to MONGODB_URI_PROD to distinguish it from MONGODB_URI_LOCAL

tsconfig.json

• add strict to the entire project

src/app.ts

• specify param types
• check for possible undefined

src/config/passport.ts

• stop using process.env
• check for possible undefined
• Set type for user parameter
• Remove "any" from serializeUser definition

src/controller/api.ts

• test for nullable token

src/controller/contact.ts

• stop using process.env

src/controller/user.ts

• stop using process.env
• check for possible undefined

src/model/user.ts

• fix bcrypt params
• fix comparePasswordFunction params

src/util/logger.ts

• stop using process.env

src/util/secrets.ts

• stop using process.env

[peterblazejewicz]

Can you redact changes to minimal set required for strity types? (.vscode are not essentials, change current behavior for autofix/autosave, package.json is not essential, etc).
Thanks!

[CarlosKlapp]

In PR #253 I replaced bcrypt-nodejs (abandoned) to bcrypt. And this code gets cleaned up as well.
I realize the callback () => {} is an ugly hack, but hope it to be temporary and replaced with a simplified promise in PR 253.
#253