Allow pluggable buffer recycling via new RecyclerPool extension point

[cowtowncoder]

Although the current hard-coder ThreadLocal-based buffer recycling (via BufferRecycler containers accessed via BufferRecyclers) has worked reasonably well up until recently, changes to later JVMs have made ThreadLocal access less beneficial; and in near future (Project Loom et al) even counter-productive.
But there are other ways to allow beneficial buffer recycling: especially for use cases where pooling is integrated with other frameworks.

To allow new default and alternative recycling schemes, let's add RecyclerPool extension point, make current implementation work with it.
And for bonus points, possibly implement one or more alternate implementations to use.

[cowtowncoder]

Note: #1064 is the current PR for implementation

[cowtowncoder]

Created issues for follow-up work for 4 modules:

• Avro and Smile format modules
• JAX-RS / Jakarta-RS providers

planning to at least tackle first 2 for 2.16, but ideally all 4.

[cowtowncoder]

Ok, realized that JAX-RS / Jakarta RS use case is NOT for Object recycling, so not related to this work -- closed issues.

Smile format use case removed altogether as FasterXML/jackson-dataformats-binary#403 (performance benefit seemed too modest to be worth it).

This leaves just Avro to be converted, hopefully by 2.16.0.