feat: [cache/memory] use ristretto as memory backend

[crandles]

Replaced the memory cache's sync.Map usage with ristretto, which has its own cost / TTL based eviction mechanism. This should be more performant than a sync.Map for concurrent read/write usage.

This allows us to skip our index client wrapper as well, for the memory provider.

Note: ristretto is utilized by the BadgerDB cache that we have an existing integration with.

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I would say the memory profile appears to have improved -- running make serve-dev with example dashboards auto-refreshing:

sum(process_resident_memory_bytes{job="trickster"}) by (instance)
sum by (instance) (go_memstats_sys_bytes{job="trickster"})
sum by (instance) (go_memstats_alloc_bytes{job="trickster"})

main vs current branch

[coveralls]

Pull Request Test Coverage Report for Build 22082628985

Details

• 42 of 55 (76.36%) changed or added relevant lines in 5 files are covered.
• 3 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.01%) to 72.064%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/cache/providers/providers.go	0	1	0.0%
pkg/frontend/options/options.go	1	3	33.33%
pkg/observability/tracing/options/options.go	1	3	33.33%
pkg/cache/memory/memory.go	39	47	82.98%

Files with Coverage Reduction	New Missed Lines	%
pkg/cache/options/options.go	1	55.29%
pkg/proxy/engines/cache_read.go	2	81.82%

Totals
Change from base Build 22071487246:	0.01%
Covered Lines:	14887
Relevant Lines:	20658

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💛 - Coveralls