[DOCS] Adds Introduction, Installation, and Connecting sections to Java client docs

[szabosteve]

Overview

This PR adds an index file, an Introduction, an Installation, and a Connecting section to the Java client docs as initial documentation.

[swallez]

Nice, thanks!

The docs folder already contains docs/design that contains internal documentation explaining some design choices. Will this cause issues if we have the public website docs in the parent docs directory?

Or should we either:

• move public docs one level deeper, e.g. docs/website,
• or move docs/design elsewhere, e.g. design_docs?

[szabosteve]

Nice, thanks!

The docs folder already contains docs/design that contains internal documentation explaining some design choices. Will this cause issues if we have the public website docs in the parent docs directory?

This shouldn't cause any issue as the public-facing docs will be generated based on the index.asciidoc file which won't contain any reference to the internal docs files. From this perspective, it's not necessary to move the files around/change the folder structure.

[szabosteve]

@swallez Thanks for the feedback, I addressed it. Please have a look at the changes and let me know if I documented the compatibility info correctly.

[philkra]

LGTM

[philkra]

Gave my LGTM, still waiting for @swallez

[swallez]

LGTM. Thanks!