feat(jaeger): better configuration pipeline.

[TommyCpp]

I think the jaeger configuration pipeline has been a little hard to understand between agent's configurations and collector's configurations. This PR:

• Separate agent pipeline and collector pipeline. it's now new_agent_pipeline and new_collector_pipeline. Note that this means if the collector exporter to start we will not fall back to agent exporter.
• Add AgentPipeline and CollectorPipeline to configure agent exporter and collector exporter.
• Add agent only configurations(auto_batches_split, max_packet_size)
• Add collector only configurations(4 build-in http clients, timeout, username, password and endpoint)
• Rename with_agent_endpoint to with_endpoint as agent pipeline and collector pipeline are separate now. Similar to collector.
• Add Configurable trait to include common attributes shared by agent pipeline and collector pipeline.
• Removed with_tag method.
• Make build-in HTTP client features(surf_collector_client, isahc_collector_client, reqwest_collector_client, reqwest_collector_blocking_client) additive.
• Make collector_client and wasm_collector_client additive. Now users can start a wasm collector using wasm_collector_client.
• Add a ConfigError for all error from the builder. Most of them are invalid value like string that cannot convert to URI
• Update the docs

Overall we seprate the collector configurations from agent configurations to prevent users set unrelevant configurations. For example,

let tracer = new_pipeline()
                 .with_agent_endpoint(...) // This confiugration will not be used if the collector is built successfully
                 .with_collector_pipeline(...)
                 .install_simple()

The downside is now if the collector fails to build, we no longer fall back to agent.

BREAKING CHANGES:
As we separate the agent pipeline and collector pipeline. The user must understand which one they are using and change new_pipeline to new_collector_pipeline or new_agent_pipeline.

Functions that contains agent or collector will no longer contains it as the pipeline are different. For example, with_collector_username will now be with_username.

For users using build in http client(isahc, reqwest, reqwest-blocking or surf). They need to add a new function to pipeline that explicitly point out the http client they want to use.

#736

[codecov]

Codecov Report

Merging #748 (498b5bc) into main (e09392d) will decrease coverage by 1.17%.
The diff coverage is 50.81%.

@@            Coverage Diff             @@
##             main     #748      +/-   ##
==========================================
- Coverage   70.19%   69.01%   -1.18%     
==========================================
  Files         108      111       +3     
  Lines        8804     8973     +169     
==========================================
+ Hits         6180     6193      +13     
- Misses       2624     2780     +156     

Impacted Files	Coverage Δ
opentelemetry-jaeger/src/exporter/agent.rs	12.50% <ø> (+0.50%)	⬆️
opentelemetry-jaeger/src/exporter/runtime.rs	0.00% <ø> (ø)
opentelemetry-jaeger/src/lib.rs	93.04% <ø> (ø)
opentelemetry-jaeger/src/exporter/collector.rs	19.00% <15.38%> (-48.86%)	⬇️
...aeger/src/exporter/config/collector/http_client.rs	25.88% <25.88%> (ø)
opentelemetry-jaeger/src/exporter/uploader.rs	19.35% <33.33%> (-4.65%)	⬇️
opentelemetry-jaeger/src/exporter/config/agent.rs	42.85% <42.85%> (ø)
opentelemetry-jaeger/src/exporter/mod.rs	56.91% <50.00%> (-2.85%)	⬇️
...emetry-jaeger/src/exporter/config/collector/mod.rs	57.96% <57.96%> (ø)
opentelemetry-jaeger/src/exporter/config/mod.rs	83.09% <83.09%> (ø)
... and 13 more

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[TommyCpp]

I think I have a way to resolve the msrv error. But it will expose HasRequiredConfig trait. Maybe we should just bump the MSRV?

[djc]

What would we need to bump it to?

[TommyCpp]

Dig a little bit and looks like the error was relaxed by rust-lang/rust#90586.
Since we cannot bring the MSRV to 1.59. I will make HasRequiredConfig public Actually we can seal it