Allow users to set custom mongodb connection URIs

[dmyerscough]

What this PR does / why we need it:

This PR allows more flexibility in configuring an external MongoDB instance. For example, MongoDB can be configured with a seed list via SRV records e.g. mongodb+srv://cluster0.example.mongodb.net.

There is an initalization container that waits for MongoDB to become available. However, we should allow this initialization container to be enabled/disabled. This is handy when using an external MongoDB instance that we know is running.

I tested this PR with the MongoDB free hosted tier. When configuring the external MongoDB instance, I set mongodb.enabled to false and set portal.server.waitForMongodb.enabled to false.

Special notes for your reviewer:

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• [x] DCO signed
• [x] Chart Version bumped
• [x] Variables are documented in the README.md

[dmyerscough]

@Jasstkn Just resigned the commit and CI looks good.

[Jasstkn]

@imrajdas @ispeakc0de @Jonsy13 hello. could you review this PR?

[dmyerscough]

@Jasstkn What's the PR process? This PR has been open for a while now and there is zero traction, should I consider this dead and just work from a forked version?

[ksatchit]

@dmyerscough - apologies on the delayed reviews. Thanks @Jasstkn for helping with increased time on this repo

The team should be able to get back to normal review cycles very soon.

Meanwhile, like the idea of providing the flag to enable/disable waitForMongo init container. Do you think it makes sense to call this out in the readme?

[uditgaurav]

Hi @dmyerscough , We already have this capability now. Please refer the README.md to know more. Feel free to reopen in case you have any thoughts.

Thanks