sql: scaffolding for db metadata update job

[xinhaoz]

This commit creates a new forever running BG job called UpdateCachedTableMetadata. This is just some scaffolding - the job doesn't do anything right now but it will be used to populate the system table storing cached table metadata used by obs surfaces.

Epic: CRDB-37558
Fixes: #127891

Release note: None

[blathers-crl]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is dev-inf.}

[cockroach-teamcity]

This change is 

[kyle-a-wong]

Just had a comment about the epic in the commit message, but otherwise,

Reviewed 8 of 17 files at r1, all commit messages.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @stevendanna and @xinhaoz)

---

-- commits line 10 at r1:
nit: This should be CRDB-37558 right?

Code quote:

Epic: none

[xinhaoz]

@kyle-a-wong Just renamed some stuff (updateCachedTableMetadata -> updateTableMetadataCache), can you re-approve if that looks good? Also added git issue and epic link!

[kyle-a-wong]

Reviewed 9 of 17 files at r1, 6 of 6 files at r3, all commit messages.
Reviewable status: complete! 0 of 0 LGTMs obtained (and 1 stale) (waiting on @stevendanna and @xinhaoz)

---

pkg/upgrade/upgradebase/testing_knobs.go line 77 at r3 (raw file):

	SkipMVCCStatisticsJobBootstrap bool

	SkipUpdateCachedTableMetadataBootstrap bool

nit: Should this be updated too, or was it left out intentionally?

Code quote:

SkipUpdateCachedTableMetadataBootstrap 

[xinhaoz]

TFTR!
bors r+

[craig]

Build succeeded:

• windows_build
• examples_orms
• macos_amd64_build
• acceptance
• docker_image_amd64
• unit_tests
• linux_amd64_fips_build
• linux_arm64_build
• local_roachtest
• check_generated_code
• macos_arm64_build
• lint
• linux_amd64_build
• local_roachtest_fips