update some GitHub links for tidb repo reorganization

[Oreoxmt]

What is changed, added or deleted? (Required)

• Update some GitHub links for pingcap/tidb repo reorganization (move most of the packages to 'pkg')
• .lycheeignore: exclude https://github\.com/\$user/(docs|docs-cn) when checking links

Which TiDB version(s) do your changes apply to? (Required)

Tips for choosing the affected version(s):

By default, CHOOSE MASTER ONLY so your changes will be applied to the next TiDB major or minor releases. If your PR involves a product feature behavior change or a compatibility change, CHOOSE THE AFFECTED RELEASE BRANCH(ES) AND MASTER.

For details, see tips for choosing the affected versions.

• master (the latest development version)
• v7.5 (TiDB 7.5 versions)
• v7.4 (TiDB 7.4 versions)
• v7.3 (TiDB 7.3 versions)
• v7.2 (TiDB 7.2 versions)
• v7.1 (TiDB 7.1 versions)
• v7.0 (TiDB 7.0 versions)
• v6.5 (TiDB 6.5 versions)
• v6.1 (TiDB 6.1 versions)
• v5.4 (TiDB 5.4 versions)
• v5.3 (TiDB 5.3 versions)
• v5.2 (TiDB 5.2 versions)
• v5.1 (TiDB 5.1 versions)
• v5.0 (TiDB 5.0 versions)

What is the related PR or file link(s)?

• This PR is translated from: update some GitHub links for tidb repo reorganization docs-cn#15221
• Other reference link(s): *: move most of the packages to 'pkg' tidb#47123

Do your changes match any of the following descriptions?

• Delete files
• Change aliases
• Need modification after applied to another branch
• Might cause conflicts after applied to another branch

[bb7133]

LGTM, thanks for the update.

[ti-chi-bot]

@bb7133: adding LGTM is restricted to approvers and reviewers in OWNERS files.

In response to this:

LGTM, thanks for the update.

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2023-10-17 05:43:34.364254421 +0000 UTC m=+1722211.951364559: ☑️ agreed by ran-huang.

[Oreoxmt]

/approve

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Oreoxmt

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[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #15114.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.2: #15115.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.3: #15116.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.4: #15117.