feat: add calcom

[ghost]

This pull request adds the one-click-application for Cal.com.

Closes #519

Checks

• I have tested the template using the method described in README.md thoroughly
• I have ensured that I put as much default values as possible (except passwords) to ensure minimum effort required for end users to get started.
• I have ensured that I am not using the "latest" tag as this tag is dynamically changing and might break the one-click app. Use a fixed version.
• I have made sure that instructions.start and instructions.end are clear and self-explanatory.
• Icon is added as a png file to the logos directory.
• I've executed the checks if necessary by running npm ci && npm run validate_apps && npm run formatter
• I will take responsibility addressing any issues that arises as a result of this PR (maintaining this app).

[githubsaturn]

Nice!!

[ThcDelux3]

I dont know excatly since which cal.com version this is the case but in the latest one this issue occurs.

When installing the calcom oneclick app you have to add an .env var manually so that the DB can be migrated:

• DATABASE_DIRECT_URL

Create that variable DATABASE_DIRECT_URL and put the same data as you have in the variable DATABASE_URL

refrences:
calcom/docker#323
calcom/docker#329 (comment)

[githubsaturn]

Added the new env vars

[ThcDelux3]

Same story again...

can you please add the env var: NEXT_PUBLIC_API_V2_URL

calcom/docker#343 (comment)

Example:
https://github.com/calcom/docker/blob/main/.env.example

could you also bump up the default version to v4.4.2