Fix DEVELOPER_README.md link in Quick Start (awslabs#45)

* Add User-Agent documentation to README

* Add User-Agent header value

* Revise documentation

README and serverless/DEVELOPER_README have been edited and now stress one-click deployment as the best way to deploy the connector.

Additionally, various grammatical, spelling, whitespace, and markdown formatting issues have been fixed. British English has been favoured. An outdated image was also changed.

GETTING_STARTED has been removed and its verification section has been moved to README.

* Fix broken & outdated links & revamp RELEASE.md

- Broken or outdated links have been fixed.
- `RELEASE.md` has been updated with instructions for using the seven public S3 buckets and `template.yml`.
- All references to version `1.1.0` have been changed to `1.0.0`.

* Update template Go version & connector version in template

- `go1.x` runtime is no longer supported for Lambda functions, causing deployments to fail, this has been updated to `provided.al2023`.
- The connector version in `template.yml` has been changed from `1.1.0` to `1.0.0`.
- Handler has been changed to `bootstrap` to match the instructions to migrate from `go1.x` to `provided.al2023`.
- The template will get the Lambda function code from the public bucket matching `AWS::Region`.
- `package.py` now names the binary `bootstrap`, but still packages the binary and documentation in an archive named `timestream-prometheus-connect-<os>-<arch>-<version>`.

* Fix DEVELOPER_README.md link in Quick Start

README.md

@@ -50,7 +50,7 @@ The Prometheus Connector receives and sends time series data between Prometheus
 
 1. [Prerequisites](#prerequisites) are met.
 2. [Prometheus is configured](#prometheus-configuration), minimum version `2.0.0`.
-3. Deploy with one click deployment: [serverless/DEVELOPER_README#deployment](serverless/DEVELOPER_README#deployment).
+3. Deploy with one click deployment: [serverless/DEVELOPER_README.md#deployment](serverless/DEVELOPER_README.md#deployment).
 4. Update `remote_read` and `remote_write` values in `prometheus.yml` to the resources created by the deployment: [serverless/DEVELOPER_README.md#configure-prometheus](serverless/DEVELOPER_README.md#configure-prometheus).
 5. [Verify the Prometheus connector is working](#verification).