Updates to documentation

[kgodey]

Fixes #3428

This PR makes the following changes:

• Minor language updates to the docs homepage.
• Removed the "Connect to an external database server" page entirely, see below.

Reasoning for page removal

The page (see live version) attempted to document two things:

(1) How to set up a Mathesar internal database if you're connecting to an external DB

These steps were out of date anyway, since they referred to configuring the DB via environment variables. Also, it is my understanding that we don't need to perform any steps after the new DB connection UI work in 0.1.4 and that we'll create the internal database automatically. So I removed it.

(2) How to configure Mathesar to point at a database on the host server if you're using Docker

My first instinct was to move this to the "Optional configurations" section of the Docker compose installation, and I spent some time doing that and making the documentation more concise. Then I realized that

• none of the documentation was about Mathesar, it's all about configuring Postgres and Docker and is probably outside the scope of our docs.
• we only document one way of doing this and present it as "the way", but there seem to be multiple approaches that can be taken to solve the problem of connecting to a Postgres database on a Docker host
• we're presuming usage of our old Docker compose file

It didn't seem like it was worth cleaning up or having this documentation, so I removed it.

Checklist

- [x] My pull request has a descriptive title (not a vague title like `Update index.md`). - [x] My pull request targets the `develop` branch of the repository - [x] My commit messages follow [best practices][best_practices]. - [x] My code follows the established code style of the repository. - [ ] I added tests for the changes I made (if applicable). - [x] I added or updated documentation (if applicable). - [x] I tried running the project locally and verified that there are no visible errors. [best_practices]:https://gist.github.com/robertpainsi/b632364184e70900af4ab688decf6f53 ## Developer Certificate of Origin

Developer Certificate of Origin

``` Developer Certificate of Origin Version 1.1 Copyright (C) 2004, 2006 The Linux Foundation and its contributors. 1 Letterman Drive Suite D4700 San Francisco, CA, 94129 Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. Developer's Certificate of Origin 1.1 By making a contribution to this project, I certify that: (a) The contribution was created in whole or in part by me and I have the right to submit it under the open source license indicated in the file; or (b) The contribution is based upon previous work that, to the best of my knowledge, is covered under an appropriate open source license and I have the right under that license to submit that work with modifications, whether created in whole or in part by me, under the same open source license (unless I am permitted to submit under a different license), as indicated in the file; or (c) The contribution was provided directly to me by some other person who certified (a), (b) or (c) and I have not modified it. (d) I understand and agree that this project and the contribution are public and that a record of the contribution (including all personal information I submit with it, including my sign-off) is maintained indefinitely and may be redistributed consistent with this project or the open source license(s) involved. ```

[kgodey]

@mathemancer please double check my reasoning here, that's the main thing I'm asking you to review.

@seancolsen also added you as a reviewer in case you wanted to look at the index page changes.

[kgodey]

@mathemancer Thanks for the feedback. As discussed on our call yesterday, I've:

• Added back the external Postgres server docs, but to the Docker Compose page.
• Added a note to the env variables docs about Caddy.

I decided not to change the build from source page because Set up the database > Step 3 already documents creating the internal database, and Install the Mathesar application > Step 2 also documents setting the environment variables. I'm not sure what we could add there.

[seancolsen]

@kgodey I think this PR should target the 0.1.5 branch now, right?