feat(amazonq): Add lsp downloading support for windows/linux

[jpinkney-aws]

Problem

• Language servers are only being downloaded on macs

Solution

• Download on windows/linux as well

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[justinmk3]

Should use fs.getUserHomeDir, it handles some edge cases.

aws-toolkit-vscode/packages/core/src/shared/fs/fs.ts

Line 596 in 02f6d0b

getUserHomeDir(): string {

And to avoid the circular dependency, getApplicationSupportFolder should live in fs.ts (and that makes sense anyways, because this is a filesystem decision).

It also seems like getApplicationSupportFolder is getting a cache dir, so maybe getCacheDir is a good name.

[justinmk3]

tryGetFilepathEnvVar may also be worth looking at in the future.

aws-toolkit-vscode/packages/core/src/shared/fs/fs.ts

Line 517 in 02f6d0b

async tryGetFilepathEnvVar(envVar: string, kind: vscode.FileType | undefined): Promise<string | undefined> {