Add temporary API docs

[thunderbiscuit]

Description

This PR adds a directory that contains the required files to build the API docs for bdk-android and bdk-jvm. The docs need to be updated and published once a release.

Notes to the reviewers

After getting comments on how specific-language API docs are useful in dev calls, I add these (albeit in a temporary fashion). We don't know how long it will be before the ability to use inline documentation is added to uniffi-rs, and so for the foreseeable future this is a good solution that will allow us to publish Kotlin API docs that work well and look good, and keep track of them in the same repository as the libraries themselves. I fully expect to remove this directory once the new workflows are in.

All Submissions:

• I've signed all my commits
• I followed the contribution guidelines

[thunderbiscuit]

I also found a way to add samples (they show up as a new tab under the given object documentation page.

[thunderbiscuit]

The current PR builds into this website.

[notmandatory]

Another nit, but I'd wrap this into multiple lines.

[thunderbiscuit]

I brought all the long lines back, but didn't apply any particular rule. Do you have one in mind that you know is standard (length of line I mean?). I'm happy to apply a bit more consistently if there is a commonly agreed way to do KDocs/Javadoc documentation.

[notmandatory]

These docs look great, but for Java and Kotlin the docs can be a bit more expressive than in Rust. I recommend using this plugin: https://plugins.jetbrains.com/plugin/10389-kdoc-generator

It allows you do type /** and return to get a basic template to fill out for the docs. The main difference from what you have now is it lets you also document the input/output parameters. Example below.

If you want to start with the short docs and fill in more details later I think what you have is fine for now.

/**
 * A blockchain client.
 *
 * @constructor Create a new blockchain client.
 *
 * @param the config for this blockchain client.
 */
class Blockchain(
    config: BlockchainConfig
) {
    /**
     * Broadcast a transaction.
     *
     * @param psbt the PSBT to broadcast.
     * @return the corresponding transaction id.
     */
    fun broadcast(psbt: PartiallySignedBitcoinTransaction): String {}

    /**
     * Get the current height of the blockchain.
     *
     * @return the block height.
     */
    fun getHeight(): UInt {}

    /**
     * Get the block hash of a given block.
     *
     * @param height the height of the block.
     * @return block hash base64 encoded.
     */
    fun getBlockHash(height: UInt): String {}
}

[thunderbiscuit]

Thanks for the plugin recommendation! Made my life much easier. All comments have been addressed, I think this is now ready for merging. We should consider filling them up a little bit before the next release with more samples, but otherwise the core is good IMO.

[notmandatory]

ACK 3f35a18

[notmandatory]

Thanks for doing all this! should help new folks get started, and also gives a great framework for filling in more docs.